Статті в журналах з теми "High impact energy dynamic compaction"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: High impact energy dynamic compaction.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 статей у журналах для дослідження на тему "High impact energy dynamic compaction".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте статті в журналах для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Jiang, Chunlin, Yanhui Ge, Baoqun Wang, Luchen Zhang, and Youbo Liu. "Impact of the High-Energy Dynamic Compaction by Multiple Compactors on the Surrounding Environment." Advances in Civil Engineering 2021 (November 29, 2021): 1–19. http://dx.doi.org/10.1155/2021/6643064.
Повний текст джерелаАнотація:
Dynamic compaction machine (DCM) is a widely adopted ground reinforcement technology. However, dynamic compaction energy has a very significant impact on the surrounding environment. At present, the research on the impact of dynamic compaction mainly focuses on the effect of the tamping behavior of a single compactor in the working state, whereas the research on the impact of multiple compactors working jointly is rare. To study the impact of the dynamic compaction energy of multiple compactors working jointly on the surrounding environment, the dynamic response model for multiple compactors working in the same field was established based on the explicit dynamic analysis module in ABAQUS. The validity of the model was verified by comparison with the measured data. Based on this, the impact of the dynamic compaction energy of multiple compactors with different working conditions in terms of the arrangement, spacing, and working time interval was analyzed. The results showed that the arrangement and spacing of the compactors had a remarkable influence on the distribution of the dynamic compaction energy in the surrounding environment. Under the condition of multiple compactors working with a time interval of less than 10 s, the impact of the superimposed dynamic compaction energy due to the interaction of multiple compactors had to be considered.
2
Jayawickrama, Priyantha W., Aruna L. Amarasiri, and Pedro E. Regino. "Use of Dynamic Cone Penetrometer to Control Compaction of Granular Fill." Transportation Research Record: Journal of the Transportation Research Board 1736, no. 1 (January 2000): 71–80. http://dx.doi.org/10.3141/1736-10.
Повний текст джерелаАнотація:
Granular material is commonly used as backfill and embedment material for buried structures, including thermoplastic pipe. Proper compaction of this material is crucial to the successful performance of the pipe. However, the commonly used Proctor density approach cannot be used for the field compaction control of these materials because it does not provide a well-defined moisture-density relationship. An alternative method used by the authors for compaction control of such materials is described. This method involves a device known as the dynamic cone penetrometer (DCP). Findings are presented from a series of DCP tests conducted on a range of granular backfill materials that belong to ASTM D 2321 Classes I and II. These materials were compacted using ( a) an impact rammer and ( b) a vibratory plate compactor. The level of compaction energy was varied by changing the number of passes. The data obtained from these tests are presented in the form of DCP blow count profiles, which are then used as the basis for comparison between different materials, compaction equipment, and levels of compaction energy. A series of full-scale load tests conducted on high-density polyethylene (HDPE) pipe installations is also described. An overview is provided of how the DCP data may be combined with load-deflection data from full-scale load tests to establish guidelines for compaction control of pipe backfill.
3
Lian, Xiaoyong, Jun Li, Housheng Jia, and Peng Ding. "The Anti-Impact Characteristics of Cables under Impact Load." Energies 16, no. 2 (January 5, 2023): 633. http://dx.doi.org/10.3390/en16020633.
Повний текст джерелаАнотація:
The cable plays a vital role in roadway support. As the last barrier to prevent roof collapse and impact disaster accidents, it is of great significance to study stress characteristics of cables under impact dynamic load to guide the rock burst roadway support. With high-strength cables of Ф21.6 and Ф21.8 mm and low-resistance high-extension cables of Ф21.5 mm as examples, this paper studied the instantaneous mechanical state and energy dissipation characteristics of different types of cables under impact loads by using impact testing machines and high-frequency data acquisition system. The results show that the impact process can strengthen the strength of the cable. The strength and elongation of anchor cables are a pair of characteristic indexes with an inverse relationship. Simply increasing one index cannot improve the overall impact resistance of the cable. To quantitatively characterize the impact resistance and energy absorption effect of cables, the impact resistance index k was introduced. The smaller the index, the better the energy absorption effect of cables. In the process of dynamic load impact of high-strength cable, about 43.7% of the total energy is dissipated disordered in the form of mechanical energy. The dynamic load impact process of low-resistance and high-extension cables is similar to the viscoelastic impact. In the collision compaction stage, the force of the cable is basically constant. Most of the impact energy is absorbed or transformed by the cable, about 17.7% of which is mostly dissipated in the form of mechanical energy. The disordered dissipated mechanical energy is less, so the impact resistance and energy absorption effect of this cable are better. The cable plays an important role in the process of bearing the dynamic load of surrounding rock. The anti-impact performance index of cables should be considered in dynamic load impact roadway support design.
4
Li, Xi, Jing Li, Xinyan Ma, Jidong Teng, and Sheng Zhang. "Numerical Study of the Dynamic Compaction Process considering the Phenomenon of Particle Breakage." Advances in Civil Engineering 2018 (December 23, 2018): 1–10. http://dx.doi.org/10.1155/2018/1838370.
Повний текст джерелаАнотація:
Dynamic compaction (DC) is commonly used to strengthen the coarse grained soil foundation, where particle breakage of coarse soils is unavoidable under high-energy impacts. In this paper, a novel method of modeling DC progress was developed, which can realize particle breakage by impact stress. A particle failure criterion of critical stress is first employed. The “population balance” between particles before and after crushing is guaranteed by the overlapping method. The performance of the DC model is successfully validated against literature data. A series of DC tests were then carried out. The effect of particle breakage on key parameters of DC including crater depth and impact stress was discussed. Besides, it is observed that the relationship between breakage amount and tamping times can be expressed by a logarithmic curve. The present method will contribute to a better understanding of DC and benefit further research on the macro-micro mechanism of DC.
5
Xue, Yongming, Bing Dai, Ying Chen, Lei Zhang, Guicheng He, and Zhijun Zhang. "Experimental Study on the Mechanical Properties and Damage Evolution of Hollow Cylindrical Granite Specimens Subjected to Cyclic Coupled Static-Dynamic Loads." Geofluids 2020 (September 22, 2020): 1–14. http://dx.doi.org/10.1155/2020/8881936.
Повний текст джерелаАнотація:
To study the characteristics of roadway surrounding rock damage caused by frequent disturbances under different static stress conditions, cyclic impact tests on granite with vertical holes under different axial prestress conditions were performed by a modified split Hopkinson pressure bar test, and the damage of the specimens was recorded with a high-speed camera process. The test results show that under the same air pressure cyclic impact, the rock specimens mainly undergo the compaction-fatigue-failure transition. As the axial prestress increases, the compaction-fatigue phase gradually weakens, and the dynamic compressive strength decreases. When the axial prestress is 42% of the UCS and 62% of the UCS, the rock specimen shows a certain “strengthening” effect during the initial cyclic impact stage. During the failure of the rock specimens, the axial prestressing effect limited the initiation of some transverse cracks, and a mixed tensile-shear failure mode appeared. The rock specimens with an axial prestress of 62% of the UCS showed energy release during cyclic impact. To some extent, the probability of “rock bursts” has been induced. Based on the one-dimensional stress wave theory, the damage variables of wave impedance during the cyclic impact loading of the rock with vertical holes are defined. It is found that when the rock specimen is in the stage of compaction and fatigue damage, the damage is small, and the damage is even reduced.
6
Li, He, Yuanbo Li, Minyu Wei, and Yi Shen. "Preparation Method of Lunar Soil Simulant and Experimental Verification of the Performance of an Impact Penetrator for Lunar Soil Exploration." Machines 10, no. 7 (July 21, 2022): 593. http://dx.doi.org/10.3390/machines10070593.
Повний текст джерелаАнотація:
The exploration and investigation of lunar soil can provide necessary information for human beings to understand the Moon’s geological evolution history and solar activity, and is also of great significance for human beings to search for new energy sources. The impact penetrator can dive to a certain depth below the lunar surface, depending on soil compaction effect, and obtain lunar soil detection data by using the onboard sensors. The penetrator has the advantages of small size, light weight, low power consumption and long-term detection ability. In order to verify the diving performance of the developed impact penetrator, a great deal of lunar soil simulant, with physical and mechanical properties similar to a real lunar soil sample, was prepared, which lay the foundation for experimental research. Experiments on the influences of mass–stiffness parameters and dynamic parameters were conducted to obtain reasonable parameter-matching effects and driving parameters. The penetrating experiments in lunar soil simulant, with different relative compaction parameters, indicated that the penetrator could penetrate the simulated lunar soil with high relative compaction, and the penetration depth could reach to 545 mm after 894 shocks in lunar soil, with a relative compaction of 85%. This study on the impact penetrator can provide a feasible approach for in-situ exploration of lunar soil.
7
Wu, Wangqing, Changsheng He, Yuanbao Qiang, Huajian Peng, and Mingyong Zhou. "Polymer–Metal Interfacial Friction Characteristics under Ultrasonic Plasticizing Conditions: A United-Atom Molecular Dynamics Study." International Journal of Molecular Sciences 23, no. 5 (March 4, 2022): 2829. http://dx.doi.org/10.3390/ijms23052829.
Повний текст джерелаАнотація:
Understanding the properties of polymer–metal interfacial friction is critical for accurate prototype design and process control in polymer-based advanced manufacturing. The transient polymer–metal interfacial friction characteristics are investigated using united-atom molecular dynamics in this study, which is under the boundary conditions of single sliding friction (SSF) and reciprocating sliding friction (RSF). It reflects the polymer–metal interaction under the conditions of initial compaction and ultrasonic vibration, so that the heat generation mechanism of ultrasonic plasticization microinjection molding (UPMIM) is explored. The contact mechanics, polymer segment rearrangement, and frictional energy transfer features of polymer–metal interface friction are investigated. The results reveal that, in both SSF and RSF modes, the sliding rate has a considerable impact on the dynamic response of the interfacial friction force, where the amplitude has a response time of about 0.6 ns to the friction. The high frequency movement of the polymer segment caused by dynamic interfacial friction may result in the formation of a new coupled interface. Frictional energy transfer is mainly characterized by dihedral and kinetic energy transitions in polymer chains. Our findings also show that the ultrasonic amplitude has a greater impact on polymer–metal interfacial friction heating than the frequency, as much as it does under ultrasonic plasticizing circumstances on the homogeneous polymer–polymer interface. Even if there are differences in thermophysical properties at the heterointerface, transient heating will still cause heat accumulation at the interface with a temperature difference of around 35 K.
8
Liu, K., and J. Zhao. "Progressive Damage Behaviours of Triaxially Confined Rocks under Multiple Dynamic Loads." Rock Mechanics and Rock Engineering 54, no. 6 (May 5, 2021): 3327–58. http://dx.doi.org/10.1007/s00603-021-02408-z.
Повний текст джерелаАнотація:
AbstractInvestigation of rock progressive damage under static confinement and strain rates facilitates the generation mechanism of natural fault damage zones. A triaxial Hopkinson bar apparatus is used to perform dynamic triaxial compression tests to examine the damage and degradation process of rocks subjected to multiple impacts. Dynamic mechanical properties are determined under a static triaxial pre-stress of (30, 20, 10) MPa and multiple dynamic loadings, with the repetitive impact velocity of 27 m/s and strain rates from 50 to 150/s. The acoustic characteristics are identified by ultrasonic measurement to qualify the damage values. The micro-crack parameters, including crack area and volumes are detected using synchrotron X-ray micro-computed tomography (μCT) to characterize the progressive damage. In addition, the microcrack orientation, density and fractal dimension are analysed from thin section. Experimental results show that dynamic stress-strain curves can be divided to elastic, nonlinear deformation and unloading phases. Dynamic peak stress, Young’s modulus and ultrasonic wave velocity decrease with increasing impact times. The high frequency of ultrasonic wave is filtered by the induced microcracks. The progressive damage and evolution of fracture networks are associated highly with microcrack initiation, propagation, branching and coalescence. Shear bands are commonly generated in granite, and tensile cracks are dominant in marble, while sandstone is mainly failed by compaction and deformation band. The absorbed energy of rock increases nonlinearly with increasing crack surface and volume. Besides, microcracks propagate primarily along the maximum principal stress; the density and fractal dimension exhibit an anisotropic distribution controlled by true triaxial confinement and dynamic impacts.
9
Halimi, Behrouz, Hamidreza Saba, Saeid Jafari MehrAbadi, and Saeid Saeidi Jam. "Laboratory study and measurement of stiffness and compaction of unsaturated clay soil by using the innovative rebound hammer." Nexo Revista Científica 34, no. 02 (June 7, 2021): 710–32. http://dx.doi.org/10.5377/nexo.v34i02.11557.
Повний текст джерелаАнотація:
Defining soil behavioral parameters, which eventually results in predicting every short-term and long-term soil behavior, has continually been one of the interests of soil mechanics and has been of exceptional value. To this end, in this study, a novel method has been reviewed to determine the compressive behavior of fine-grained soils in the laboratory and the field, without sampling by the patented electronic device. In the lab, homogeneous materials of the intended soil underwent the compaction test, mechanical and physical tests, direct shear test, and impacts of the innovative rebound hammer in the horizontal and vertical directions in the test-box. The impact shear waves produce resistance and voltage output by force and dislocation sensors with high-sensitivity proportional to the pressure based on the soil surface stiffness. The obtained voltages are then converted to digital by an analog-to-digital converter and a microcontroller. Next, a number is shown on display by the "CodeVision" program. Then, by solving a quasi-dynamic equation (Viscoelastic spring-damper model) by MATLAB software and with the aid of laboratory-field results and correlation equations, a fitting connection between all effective mechanical soil parameters has been estimated to an acceptable extent. The effective mechanical parameters of the soil include the compaction percentage, specific gravity, and frequency of the system in the damped and non-damped states, the energy imposed on the soil, and the plastic stage strain in the range of less than 15% humidity. The results determine that increased hammering numbers are directly related to increased soil compaction and stiffness. In more detail, the reading of hammer numbers less than 2 corresponds to compaction of less than 75%, while the reading of hammer numbers greater than 3 in the vertical and 2.94 in the horizontal directions on clay surfaces designates compaction of 90%.
10
Xu, Dong, Mingshi Gao, Yichao Zhao, Yongliang He, and Xin Yu. "Study on the Mechanical Properties of Coal Weakenedby Acidic and Alkaline Solutions." Advances in Civil Engineering 2020 (October 10, 2020): 1–15. http://dx.doi.org/10.1155/2020/8886380.
Повний текст джерелаАнотація:
A novel method for fracturing coal is presented in this paper. A chemical solution is injected into coal under high pressure, whereby the coal is fractured and subsequently weakened by chemical erosion over time to produce an anti-impact soft structure. In this study, the mechanical properties of coal under chemical erosion were investigated, and the fracturing design parameters were optimized. The uniaxial compression test and the split Hopkinson pressure bar (SHPB) test were used to determine the dynamic and static mechanical properties of coal after 20 days of immersion in different chemical solutions. After chemical solution erosion, the dynamic and static compressive strengths and elastic modulus of the coal decreased according to an exponential power law in the damage variable. The chemical treatment increased the duration of the pore compaction stage and decreased that of the elastic deformation stage, while decreasing the brittleness and increasing the ductility of coal. The acoustic emission (AE) curve of the immersed coal samples consisted of four stages corresponding to those of the stress-strain curve: pore compaction-closure, a slowly rising linear elastic regime, steady-state prepeak crack propagation, and unsteady crack propagation at the peak strain. The increase in the damage variable of the coal sample from chemical erosion led to a lower dissipated energy, a higher fractal dimension, and a more fragmented coal sample. The effect of the investigated chemical solutions on weakening the coal mechanical properties decreased in the following order: alkaline solution > acidic solution > NaCl solution > distilled water. The experimental results provide a reference for weakening fractured coal seams.
11
ZHAO, GUIPING, SANG-KYO LEE, and CHONGDU CHO. "EFFECT OF COMPRESSIVE RESIDUAL STRESS INDUCED DURING FABRICATING PROCESS IN THE CORE OF CLAMPED SANDWICH PLATE UNDER SHOCK LOADING." International Journal of Modern Physics B 22, no. 09n11 (April 30, 2008): 1195–200. http://dx.doi.org/10.1142/s0217979208046530.
Повний текст джерелаАнотація:
Sandwich panels can be manufactured in many ways like lamination press, closed mold fabrication, and vacuum bag compaction. During manufacturing, the core and the sheets are attached under certain applied pressure and temperature, associated with a deformation and stress remaining in the sandwich core. This study presents an evaluation of the compressive residual stress effect of the core which occurs during the localized shock loading at the mid-span of a clamped sandwich plate. We simulate such a square lattice core sandwich plate by commercial finite element code, ABAQUS/Explicit. We apply uniform distributed loading on upper face sheet and temperature difference occurred during the manufacturing process is taken here before the impact simulation step. These loadings induce certain amount of residual stresses in core structure of sandwich panel. The computational result from non-residual stress case is verified by comparing with the results of published experimental data on similar investigation. In addition, the effect of existing residual stress at core is analyzed. We also compare the dynamic responses of two clamped sandwich plates with and without pre-stressed core. And impact resistance of sandwich panel is explained in the view of energy capacity. Results show that the shock loading behavior of sandwich panel depends on its manufacturing process and panels with compressive residual stresses have less deformation and high impact energy absorption characteristics.
12
Wang, Wei, Zhonghao Zhang, Qing Huo, Xiaodong Song, Jianchao Yang, Xiaofeng Wang, Jianhui Wang, and Xing Wang. "Dynamic Compressive Mechanical Properties of UR50 Ultra-Early-Strength Cement-Based Concrete Material under High Strain Rate on SHPB Test." Materials 15, no. 17 (September 5, 2022): 6154. http://dx.doi.org/10.3390/ma15176154.
Повний текст джерелаАнотація:
UR50 ultra-early-strength cement-based self-compacting high-strength material is a special cement-based material. Compared with traditional high-strength concrete, its ultra-high strength, ultra-high toughness, ultra-impact resistance, and ultra-high durability have received great attention in the field of protection engineering, but the dynamic mechanical properties of impact compression at high strain rates are not well known, and the dynamic compressive properties of materials are the basis for related numerical simulation studies. In order to study its dynamic compressive mechanical properties, three sets of specimens with a size of Φ100 × 50 mm were designed and produced, and a large-diameter split Hopkinson pressure bar (SHPB) with a diameter of 100 mm was used to carry out impact tests at different speeds. The specimens were mainly brittle failures. With the increase in impact speed, the failure mode of the specimens gradually transits from larger fragments to small fragments and a large amount of powder. The experimental results show that the ultra-early-strength cement-based material has a greater impact compression brittleness, and overall rupture occurs at low strain rates. Its dynamic compressive strength increases with the increase of strain rates and has an obvious strain rate strengthening effect. According to the test results, the relationship curve between the dynamic enhancement factor and the strain rate is fitted. As the impact speed increases, the peak stress rises, the energy absorption density increases, and its growth rate accelerates. Afterward, based on the stress–strain curve, the damage variables under different strain rates were fitted, and the results show that the increase of strain rate has a hindering effect on the increase of damage variables and the increase rate.
13
Panteleenko, F. I., V. A. Okovity, O. G. Devоino, V. M. Astashinsky, and F. Switala. "Multi-Layers Composite Plasma Coatings Based on Oxide Ceramics and M-Croll." Science & Technique 21, no. 2 (April 6, 2022): 93–98. http://dx.doi.org/10.21122/2227-1031-2022-21-2-93-98.
Повний текст джерелаАнотація:
The paper considers the influence of the parameters of the plasma spraying process on the technological characteristics of multilayer coatings based on nickel-chromium, nickel-chromium-aluminum-yttrium materials, oxide ceramics, intended for operation at high temperature and additional dynamic loads. The design of plasma coatings during their application (with subsequent high-energy processing) under such conditions requires a comprehensive solution – both the use of high-quality powder ingredients and the optimization of technological parameters. The plasma process of applying powder materials has been improved to obtain the maximum values of their utilization factors. The technological characteristics that affect the properties of plasma coatings are optimized, namely: the flow rates of the plasma-forming and materials-transporting gases, the flow rate of supplied powder materials, the current and voltage of the electric arc of the plasma torch, the distance from the plasma torch nozzle exit to the substrate. The paper presents the results of studies of the structure of coatings, performed using scanning electron microscopy. Their analysis has made it possible to form general regularities obtained by the action of radiation of compression plasma flows on coatings formed by air plasma. The considered structures are created using the processes of melting, compaction and high-speed cooling of plasma coatings. The main optimization indicators are the maximum local compaction and spillage of the obtained compositions with the absence of defects and destruction from the impact of compression plasma flows. The main effect during the action of radiation of a compression plasma flow on previously formed coatings is thermal. It contributes heating of the near-surface layer. When the coating is exposed to radiation of compression plasma flows, a remelted layer of oxides with a thickness of about 12–15 µm is created, smoothing the relief of the formed surface and creating a network of cracks on the surface, diverging into the depth of the coating. The liquid-phase processes occurring in the molten phase of the near-surface layers after exposure to compression plasma radiation change the structure of the layers and contribute to the modification of their mechanical properties. By smoothing the surface, increasing the density of the surface crystallized layer and minimizing macro-defects – pores or macrocracks – the mechanical characteristics of the coatings increase.
14
Pan, Kaiming, Rena C. Yu, Xiaoxin Zhang, Gonzalo Ruiz, and Zhimin Wu. "Propagation Speed of Dynamic Mode-I Cracks in Self-Compacting Steel Fiber-Reinforced Concrete." Materials 13, no. 18 (September 12, 2020): 4053. http://dx.doi.org/10.3390/ma13184053.
Повний текст джерелаАнотація:
The objective of this study is to measure the crack propagation speed in three types of self-compacting concrete reinforced with steel fibers loaded under four different loading rates. Central-notched prismatic beams with two types of fibers (13 mm and 30 mm in length), three fiber volume ratios, 0.51%, 0.77% and 1.23%, were fabricated. Four strain gages were glued on one side of the specimen notch to measure the crack propagation velocity, a fifth one at the notch tip to estimate the strain rates upon the initiation of a cohesive crack and the stress-free crack. A servo-hydraulic testing machine and a drop-weight impact device were employed to conduct three-point bending tests at four loading-point displacement rates, the former to perform tests at 2.2 μm/s, 22 mm/s and the latter for those at 1.77 m/s, 2.66 m/s, respectively. With lower fiber contents, smooth mode-I cracks were formed, the crack speed reached the order of 1 mm/s and 20 m/s. However, crack velocities up to 1417 m/s were obtained for the concrete with high content of fibers under impact loading. This value is fairly close to the theoretically predicted terminal crack velocity of 1600–1700 m/s. Numerical simulations based on cohesive theories of fracture and preliminary results based on the technique of Digital Image Correlation are also presented to complement those obtained from the strain gages. In addition, the toughness indices are calculated under all four loading rates. Strain hardening (softening) behavior accounting from the initiation of the first crack is observed for all three types of concrete at low (high) loading rates. Significant enhancement in the energy absorption capacity is observed with increased fiber content.
15
Oberst, Sebastian, Johanna Baetz, Graeme Campbell, Frank Lampe, Joseph C. S. Lai, Norbert Hoffmann, and Michael Morlock. "Vibro-acoustic and nonlinear analysis of cadavric femoral bone impaction in cavity preparations." MATEC Web of Conferences 148 (2018): 14007. http://dx.doi.org/10.1051/matecconf/201814814007.
Повний текст джерелаАнотація:
Owing to an ageing population, the impact of unhealthy lifestyle, or simply congenital or gender specific issues (dysplasia), degenerative bone and joint disease (osteoarthritis) at the hip pose an increasing problem in many countries. Osteoarthritis is painful and causes mobility restrictions; amelioration is often only achieved by replacing the complete hip joint in a total hip arthroplasty (THA). Despite significant orthopaedic progress related to THA, the success of the surgical process relies heavily on the judgement, experience, skills and techniques used of the surgeon. One common way of implanting the stem into the femur is press fitting uncemented stem designs into a prepared cavity. By using a range of compaction broaches, which are impacted into the femur, the cavity for the implant is formed. However, the surgeon decides whether to change the size of the broach, how hard and fast it is impacted or when to stop the excavation process, merely based on acoustic, haptic or visual cues which are subjective. It is known that non-ideal cavity preparations increase the risk of peri-prosthetic fractures especially in elderly people. This study reports on a simulated hip replacement surgery on a cadaver and the analysis of impaction forces and the microphone signals during compaction. The recorded transient signals of impaction forces and acoustic pressures (≈ 80 μs - 2 ms) are statistically analysed for their trend, which shows increasing heteroscedasticity in the force-pressure relationship between broach sizes. Tikhonov regularisation, as inverse deconvolution technique, is applied to calculate the acoustic transfer functions from the acoustic responses and their mechanical impacts. The extracted spectra highlight that system characteristics altered during the cavity preparation process: in the high-frequency range the number of resonances increased with impacts and broach size. By applying nonlinear time series analysis the system dynamics increase in complexity and demand for a larger minimum embedding dimension. The growing number of resonances with similar level of the transfer function indicates a higher propensity to dissipate energy over sound; the change in embedding dimension indicates a decrease in linearity. The spectral changes as well as the altered dimension requirements indicate either an improved coupling between the bone and the broach or the onset of micro-fractures caused by growing stress levels within the bone.
16
Ostrowski, Krzysztof Adam, Roman Kinasz, and Piotr Dybeł. "The Impact of Surface Preparation for Self-Compacting, High-Performance, Fiber-Reinforced Concrete Confined with CFRP Using a Cement Matrix." Materials 13, no. 12 (June 24, 2020): 2830. http://dx.doi.org/10.3390/ma13122830.
Повний текст джерелаАнотація:
With the development of concrete technology, the tendency to combine different materials with each other to achieve a greater efficiency and durability of structures can be observed. In the modern construction industry, various materials and techniques are increasingly being combined in order to achieve e.g., an increased resistance to dynamic impacts of a structure, or an increased scope of work of a selected constructional element, which translates into a significant increase in the energy of destruction. Thus, hybrid elements, known as composite ones, are created, which consist of concrete and reinforcements. This study examined the influence of the preparation of the concrete surface on the behavior of high-performance, self-compacting, fiber-reinforced concrete (HPSCFRC), reinforced with carbon fibers (CF) using a cement matrix. In the general lamination processes, this is preformed using epoxy resin. However, epoxy resin is sensitive to relatively low temperatures, and therefore the authors attempted to use a cement matrix in the lamination process. When connecting hardened concrete with a fresh concrete matrix or mixture, the type of the concrete surface is significant. In this research, three types of concrete surfaces e.g., unprepared, sanded and grinded were considered. All of the surfaces were examined using a 3D laser scanner, to determine the Abbott-Firestone profile material share curve. In this research, cylindrical concrete specimens were reinforced with one, two and three layers of laminates. They were then subjected to a uniaxial compressive test. The results of tests showed that the use of cement matrix in the lamination process, due to its low efficiency, should not be applied when reinforcing concrete elements with a high compressive strength. Moreover, the grinded surface of concrete showed the best cooperation with CF reinforcement.
17
Quan, Enmao, Hongke Xu, and Zhongyang Sun. "Composition Optimization and Damping Performance Evaluation of Porous Asphalt Mixture Containing Recycled Crumb Rubber." Sustainability 14, no. 5 (February 25, 2022): 2696. http://dx.doi.org/10.3390/su14052696.
Повний текст джерелаАнотація:
Composition optimization of the asphalt mixture of pavement is one effective measures to reduce the harm of traffic noise. To improve the noise reduction effect of porous asphalt mixture (PAM) and promote the recycling of crumb rubber in highway engineering, the preparation parameters of high-viscosity modified asphalt for PAM were optimized in this study, and the mixture gradation was optimized based on the unbalance force and contact force of mixed aggregate. The effects of crumb rubber content and particle size on the damping performance and dynamic shear modulus of the mixture were studied. The effects of different preparation parameters on the performance of the PAM were comprehensively evaluated based on the orthogonal test, and preparation parameters of PAM were recommended. The results show that with the increase of crumb rubber content, the damping ratio of the mixed aggregate increases gradually. The addition of crumb rubber is conducive to improving the damping performance and toughness of the PAM, but it has an adverse impact on the bearing capacity. Under the condition of low strain, the damping ratio of the mixed aggregate containing 2–5 mm crumb rubber is 1.2–5 times that of the mixed aggregate containing 0.6–1 mm crumb rubber. The recommended optimum content of crumb rubber in PAM is 4%, and the optimum particle size of alternative aggregate is 2.36–4.75 mm. The significant factors affecting Marshall stability are rubber particle content, asphalt aggregate ratio, mixing temperature, compaction times, and forming temperature. The rational utilization of crumb rubber in PAM is of positive significance to promoting the green development of highway construction and the harmless treatment of waste resources.
18
Altawati, Faisal, Hossein Emadi, and Rayan Khalil. "An experimental study to investigate the physical and dynamic elastic properties of Eagle Ford shale rock samples." Journal of Petroleum Exploration and Production Technology 11, no. 9 (July 26, 2021): 3389–408. http://dx.doi.org/10.1007/s13202-021-01243-w.
Повний текст джерелаАнотація:
AbstractUnconventional resources, such as Eagle Ford formation, are commonly classified for their ultra-low permeability, where pore sizes are in nano-scale and pore-conductivity is low, causing several challenges in evaluating unconventional-rock properties. Several experimental parameters (e.g., diffusion time of gas, gas injection pressure, method of permeability measurement, and confining pressure cycling) must be considered when evaluating the ultra-low permeability rock's physical and dynamic elastic properties measurements, where erroneous evaluations could be avoided. Characterizing ultra-low permeability samples' physical and elastic properties helps researchers obtain more reliable information leading to successful evaluations. In this study, 24 Eagle Ford core samples' physical and dynamic elastic properties were evaluated. Utilizing longer diffusion time and higher helium injection pressure, applying complex transient method, and cycling confining pressure were considered for porosity, permeability, and velocities measurements. Computerized tomography (CT) scan, porosity, permeability, and ultrasonic wave velocities were conducted on the core samples. Additionally, X-ray Diffraction (XRD) analysis was conducted to determine the mineralogical compositions. Porosity was measured at 2.07 MPa injection pressure for 24 h, and the permeability was measured using a complex transient method. P- and S-wave velocities were measured at two cycles of five confining pressures (up to 68.95 MPa). The XRD analysis results showed that the tested core samples had an average of 81.44% and 11.68% calcite and quartz, respectively, with a minor amount of clay minerals. The high content of calcite and quartz in shale yields higher velocities, higher Young's modulus, and lower Poisson's ratio, which enhances the brittleness that is an important parameter for well stimulation design (e.g., hydraulic fracturing). The results of porosity and permeability showed that porosity and permeability vary between 5.3–9.79% and 0.006–12 µD, respectively. The Permeability–porosity relation of samples shows a very weak correlation. P- and S-wave velocities results display a range of velocity up to 6206 m/s and 3285 m/s at 68.95 MPa confining pressure, respectively. Additionally, S-wave velocity is approximately 55% of P-wave velocity. A correlation between both velocities is established at each confining pressure, indicating a strong correlation. Results illustrated that applying two cycles of confining pressure impacts both velocities and dynamic elastic moduli. Ramping up the confining pressure increases both velocities owing to compaction of the samples and, in turn, increases dynamic Young's modulus and Poisson's ratio while decreasing bulk compressibility. Moreover, the results demonstrated that the above-mentioned parameters' values (after decreasing the confining pressure to 13.79 MPa) differ from the initial values due to the hysteresis loop, where the loop is slightly opened, indicating that the alteration is non-elastic. The findings of this study provide detailed information about the rock physical and dynamic elastic properties of one of the largest unconventional resources in the U.S.A, the Eagle Ford formation, where direct measurements may not be cost-effective or feasible.
19
Poran, Chaim J., and Jorge A. Rodriguez. "Design of dynamic compaction." Canadian Geotechnical Journal 29, no. 5 (October 1, 1992): 796–802. http://dx.doi.org/10.1139/t92-087.
Повний текст джерелаАнотація:
In recent years dynamic compaction (DC) has become a popular method for deep improvement of loose cohesionless soils and man-made fills of disposed waste and rubble. One of the main problems facing design engineers and contractors is the assessment of the number of tamper drops, grid spacing, and layout of passes required to attain satisfactory improvement depth in the soil strata. Many DC sites have irregular subsurface conditions where it is difficult to interpret results from site exploration and verification tests. The industry has long been using a simple relationship to estimate the depth of improvement (influence depth). The estimates obtained from that empirical method may vary considerably and in many cases may be rendered useless for DC design. The paper describes a new, rational, and more comprehensive DC design method based on results from an extensive experimental model study of impact response in dry sand. Analysis of normalized impact energy and the resulting densification in the sand in terms of normalized dimensions of volumetric strain contours shows unique correlations that are used for the proposed design method for dynamic compaction in unsaturated sandy soils. Data from several DC sites fit well with the new method. With future studies of field results the proposed approach could eventually be calibrated and used for other types of soil conditions. Key words : dynamic compaction, design, impact, sandy soil, energy, plastic strains
20
Feng, Shi-Jin, Ke Tan, Wei-Hou Shui, and Yan Zhang. "Densification of desert sands by high energy dynamic compaction." Engineering Geology 157 (May 2013): 48–54. http://dx.doi.org/10.1016/j.enggeo.2013.01.017.
Повний текст джерела
21
Li, Qian, Chuan Tang, Le Fu, Xiao Ming Cao, Pei Zhen Chen, Gao Wang, Qiang Yang, et al. "Practice Research on Wet-Collapsible Loess Foundation Treatment by High Energy Dynamic Compaction." Applied Mechanics and Materials 204-208 (October 2012): 635–39. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.635.
Повний текст джерелаАнотація:
A systematic and comprehensive study on the design, construction and testing of large scale of Ⅲ～Ⅳ grade wet-collapsible loess foundation treatment by 8000 kN•m high energy dynamic compaction is done in this paper. Effect on the treatment for collapsible loess foundation by dynamic compaction is analyzed through Rayleigh wave velocity test, standard penetration test, lab soil test and static cone penetration test. By comparison with physical and mechanical properties index of the foundation soil without dynamic compaction treatment, the effective reinforcement depth, the elimination of collapsibility and the bearing capacity of foundation are found to meet the design requirements. The results of this paper could supply some reference for the design, construction and testing of other collapsible loess foundations by dynamic compaction treatment.
22
Jiang, Yang, Yue Xin She, Wen Bin Sun, Bao Hai Chen, and Hua Rong Shen. "Consolidation Effect and Influencing Factors of Dynamic Compaction for Filling Subgrade." Applied Mechanics and Materials 204-208 (October 2012): 1617–21. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.1617.
Повний текст джерелаАнотація:
The parameters of dynamic compaction impacting on consolidation effect such as fall-height of hammer, impact mode, impact space, etc. are analysed by dynamic FEM method. The method of choosing parameters of dynamic compaction and consolidation effect of dynamic compaction on filling subgrade are illuminated by field test. Conclusions are drawn: with the increase of impact energy, the range of plastic deformation zone will extend to a certain depth in subgrade, which will certainly expand the effective reinforcement range of subgrade; optimal impact times of a subgrade is available; the consolidate depth and influencing area by light hammer with heavy impact is less than that by heavy hammer with light impact when impact energy is equal; with the increase of hammer diameter, both deformation and strain of subgrade reduce under the same impact energy.
23
Han, Yunshan, Yanli Dong, Yuanlong Wang, Wei Duan, and Weihua Qin. "Experiment Study of Loess-filled Embankment under Dynamic Compaction." Open Civil Engineering Journal 9, no. 1 (September 10, 2015): 644–49. http://dx.doi.org/10.2174/1874149501509010644.
Повний текст джерелаАнотація:
To investigate the dynamic compaction mechanism of loess-filled embankment, a computational model of unit volume compaction effort was proposed as compared with the compaction test. The energy level of dynamic compaction used in actual projects was also considered. The differences between the compaction test and the unit volume compaction effort in the actual projects were studied. And also, the unit volume compaction efforts of the main tamping point and the whole reinforcement scope were analyzed. It can be drawn out that the compaction criterion should be chosen based on the water content of loess on site. Based on the model test, the laws of acceleration, velocity and displacement under the dynamic impact of hammer on the loess-filled embankment were analyzed in our study. The whole process also perfectly explained the movement history of hammer under dynamic compaction and the work-energy conversion efficiency of dynamic compaction.
24
Pan, Xiang Hong, Zhan Yong Yao, Kai Zhang, and Zhuang Jin. "Highway Subgrade Dynamic Response Model Test Study on Foundation-Broaden Dynamic Compaction Consolidation." Applied Mechanics and Materials 353-356 (August 2013): 842–46. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.842.
Повний текст джерелаАнотація:
While widen the highway foundation, due to it is still unclear that the law of dynamic compaction vibration impact on the original subgrade and foundation structure , which restricts the use of dynamic compaction technology in the highway foundation-broaden project. In this paper, by using the dynamic compaction indoor model test, simulated the dynamic compaction road widening foundation works, monitored the vibration acceleration of the pavement and subgrade surface in the process of dynamic compaction vibration, analyzed the dynamic compaction vibration propagation law of the roadside foundation in the subgrade structure. At the same time, we made the vibration amplitude of the key points and the rammer subsoil dynamic pressure value as double assessment indicators. Besides, we analyzed the dynamic compaction vibration response of subgrade under different parameters, evaluated foundation reinforcement effect. With research, under the same tamping energy and in a certain range of rammer diameter and weight, we had better choose small radius rammer and the compaction process of heavier rammers dropping from lower point, which can reduce the foundation dynamic vibration of the old subgrade and ensure foundation reinforcement effect.
25
Parvizi, M. "Soil Response to Surface Impact Loads During Low Energy Dynamic Compaction." Journal of Applied Sciences 9, no. 11 (May 15, 2009): 2088–96. http://dx.doi.org/10.3923/jas.2009.2088.2096.
Повний текст джерела
26
Feng, Shi-Jin, Wei-Hou Shui, Li-Ya Gao, and Li-Jun He. "Application of High Energy Dynamic Compaction in Coastal Reclamation Areas." Marine Georesources & Geotechnology 28, no. 2 (May 20, 2010): 130–42. http://dx.doi.org/10.1080/10641191003780815.
Повний текст джерела
27
Zhang, Lu, Guangqing Yang, Dongliang Zhang, Zhijie Wang, and Jing Jin. "Field Test and Numerical Simulation of Dynamic Compaction of High Embankment Filled with Soil-Rock." Advances in Civil Engineering 2019 (September 10, 2019): 1–9. http://dx.doi.org/10.1155/2019/6040793.
Повний текст джерелаАнотація:
In view of the high filling height and large amount of soil and rock in the high-filled embankment, the variation law of the displacement field, stress field, and plastic zone of embankment body reinforced by dynamic compaction with different energy levels and the optimal compaction energy were analyzed by means of numerical simulations and field tests. Taking the embankment section of the Ping-Zan highway as an example, the construction scheme of dynamic compaction was designed, and the optimum tamping times and effective dynamic compaction depth of the embankment filled with soil-rock were obtained through the field test. The study showed that the displacement field and the stress field are redistributed after applying single-point compaction, and the volume of the shear plastic zone increases. The optimal number of slams for high-filled granular soil is 7 times, and the effective depth of dynamic compaction is 4.5 m. The result corresponds with that by the field test, which indicates that dynamic compaction is reasonable and has a significant effect on the high embankment filled with granular soil.
28
Yuan, Yu Qing, Xuan Cang Wang, and Hui Jun Shao. "Study on Impact Compaction of Aeolian Sand Subgrade and its Effect Evaluation." Advanced Materials Research 378-379 (October 2011): 370–73. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.370.
Повний текст джерелаАнотація:
In order to solve the problem of aeolian sand subgrade compaction, we studied the technology of impact compaction, applied it to the engineering practice and analyzed its effect with Rayleigh wave. The technology of impact compaction can combine the compaction of potential energy and kinetic energy and make it easier for the materials to reach their elastic stage. With the combined function of "knead-roll-impact", the impact compaction road roller can compact the soil body and offer 6～10 times impact force and 3～4 times the depth of influence more than the vibratory roller. The impact compaction methods of aeolian sand subgrade were put forward. The comparative field compaction tests between impact and vibratory compaction are carried through, which are detected by Rayleigh wave. The results show that the impact compaction can make the density of the aeolian sand subgrade 2～5% higher than the vibratory compaction, and reach the influence depth of 7 metres. To sum up, the impact compaction can clearly increases the strength and stiffness of aeolian sand subgrade with a dynamic elastic modulus of 202.63MPa.
29
Zhou, Chong, Chenjun Yang, Hui Qi, Kai Yao, Zhanyong Yao, Kai Wang, Ping Ji, and Hui Li. "Evaluation on Improvement Zone of Foundation after Dynamic Compaction." Applied Sciences 11, no. 5 (February 28, 2021): 2156. http://dx.doi.org/10.3390/app11052156.
Повний текст джерелаАнотація:
Dynamic compaction (DC) is one of the most popular methods for ground improvement. To solve the problem of the factors affecting the sandy soil improvement effect and estimate the effective improvement range under DC, the influences of drop number, drop energy, tamping distance, tamper radius, and drop momentum on the relative degree of improvement were investigated. Three normalized indicators △δz,i, △δA,i, and △δU,i were derived to evaluate the weak zone and corresponding improvement effect. For multipoint tamping, it is found that the improvement depth and the improvement of the weak zone are highly correlated with drop energy and drop momentum, while the influence of the drop number and tamper radius is relatively smaller. The improvement of the weak zone and the improvement depth decrease with tamping distance, whereas the improvement area increases with tamping distance. The soil compacted by the previous impact point will be improved to a lesser extent with impact at subsequent impact points. It is also noted that drop energy had better not exceed the saturated drop energy in DC design. Based on the parametric study, a formula considering the various factors of DC was put forward, with the validation by two field cases of DC.
30
Gao, Zheng Guo, Yu Long Du, Xiao Bo Huang, and Xin Huang. "Mechanical Behavior of Broken Stone Fills under Dynamic Consolidation." Advanced Materials Research 446-449 (January 2012): 1696–702. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.1696.
Повний текст джерелаАнотація:
This paper studies the dynamic response characteristics of broken stone fills. Numerical simulation and in-situ test of the acceleration and settlement of a high fill under dynamic consolidation are carried out. The result shows that increasing compact energy and the compact numbers can improve the reinforcement effect. There is no significant relationship between the dynamic compaction number reaching the stable settlement and compact energy. When the compact energy is the same, compaction with a heavier hammer is better than compaction with a lighter hammer.
31
Chen, Jin, Zhi Yu Xiao, Chao Jie Li, San Cai Deng, Tung Wai Leo Ngai, and Yuan Yuan Li. "High Velocity Compaction of 316L Stainless Powder." Applied Mechanics and Materials 44-47 (December 2010): 2993–97. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.2993.
Повний текст джерелаАнотація:
High velocity compaction technology was used to press 316L stainless powders. Effects of impact times on stress wave, green density and ejection force were analyzed. It was found that under the same total impact energy, the first loading time and the actuation duration of the second impact in double impact process were longer when compared with single impact process, while the first delay time was shorter. Furthermore, the green density of compacts prepared by double impact was greater than that prepared by single impact, but no obvious variation in maximum ejection force can be observed between single impact and double impact process.
32
Moon, Joon-Shik, Hyuk Sang Jung, Sungjune Lee, and Su-Tae Kang. "Ground Improvement Using Dynamic Compaction in Sabkha Deposit." Applied Sciences 9, no. 12 (June 19, 2019): 2506. http://dx.doi.org/10.3390/app9122506.
Повний текст джерелаАнотація:
The sabkha soil spreads extensively in the Arabian Gulf Coast region. Sabkha is known as a geotechnically problematic soil because of its loose density, soft consistency, high salinity and water content, and occurrence of fine sands and clays. It is generally highly compressible and requires ground improvement for highway and railway construction. The purpose of this study is to provide a guideline for dynamic compaction to improve the bearing capacity of the coastal sabkha deposit. The ground behavior during dynamic compaction was evaluated for various compaction energy conditions using numerical analysis, and field dynamic compaction tests were also performed and compared with the numerical analysis results. It was found that the bearing capacity of sabkha deposit can be effectively improved by dynamic compaction. However, care must be taken to ensure that excessive porewater pressure is sufficiently dissipated during the application of dynamic compaction because the permeability is pretty low due to the high salt content in groundwater in the sabkha area.
33
Mei, Yuan, Chang Ming Hu, and Xue Yan Wang. "Experimental Research on Deep Collapsible Loess Foundation Treatment by Dynamic Compaction under Super High Fill." Applied Mechanics and Materials 256-259 (December 2012): 129–38. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.129.
Повний текст джерелаАнотація:
Taking one foundation project as an example, a series of tests are carried out to study the dynamic compaction parameters and its effects on the deep collapsible loess foundation under super high fill in Lvliang region. Analyses are made on the average settlement of each test area before and after dynamic compaction and on the regularity of the main physical and mechanical indexes of soil. At the energy levels of 2000 kN•m, 3000kN•m and 6000kN•m, the main parameters are gained, such as the effective reinforcement depth, the centre distance of tamping points , the standard of stopping ramming, and the optimal ramming number; hence, the empirical formula of the effective reinforcement depth of dynamic compaction. The results of the tests show that the deep collapsible loess foundation in Lvliang region can be effectively reinforced by dynamic compaction, that the stability of foundation is good, and that the loess collapse in the reinforced range is eliminated basically. Moreover, after dynamic compaction above the energy levels of 2000 kN•m, the eigenvalue of the bearing capacity of collapsible loess foundation in Lvliang can reach over 300kPa; the deformation modulus of foundation soil is more than 25MPa. Therefore, the results of the tests can provide a reference for the design and construction of projects of the same kind; it can also provide a reliable basis for relevant norms and standards.
34
Vincent, Gilles, Bernard Corre, and Pierre Thore. "Managing Structural Uncertainty in a Mature Field for Optimal Well Placement." SPE Reservoir Evaluation & Engineering 2, no. 04 (August 1, 1999): 377–84. http://dx.doi.org/10.2118/57468-pa.
Повний текст джерелаАнотація:
Summary This paper describes a reservoir simulation study of a mature field. The objective of the study was to decide whether to drill an additional well and, if so, to determine its optimum location. An original approach to history-matching the model and accounting for structural uncertainty was adopted and we come to the following conclusions:The structural map can be used as a history matching parameter,Maps with the same original oil in place (OOIP) can lead to quite different productions,The same production can be obtained from different maps having different OOIP,The choice of complementary development schemes must take the nonuniqueness of the history match into account in order to minimize risk,Demonstration of the use of experimental design techniques in accounting for and managing structural uncertainty. Introduction For a developed field, the matching of the production history of the existing wells in a dynamic simulation is done by varying the usual parameters such as aquifer thickness, pore volume, petrophysics, relative permeabilities, fluids, etc. but seldom by making changes to the structural map. The latter is determined during the course of the static study [calculation of original oil in place (OOIP)] of a field and is generally not altered thereafter except, possibly, very locally. In the context of additional development, once a match is obtained, the location of one or more extra wells is determined on the basis of the structural image chosen. But there are nearly always uncertainties outside of the zone calibrated at well locations, and there may affect flow and, consequently, matching and additional reserve estimates. In what follows, consideration of the structural uncertainty led us to generate several possibilities for the top reservoir map and to propose an original approach for managing the multiple cases both for production history matching of the field and for choosing the location of an additional development well. Presentation of the Field The field studied here is a mature field with data available from six wells, three of which are production wells (P1, P2, and P6), the others being abandoned exploration or appraisal wells (Fig. 1) (one of these wells is used for produced water disposal). It has a production history of 11 years and current water cuts of 70%-90%. The hydrocarbon produced is dead oil (no gas) and the extremely thick aquifer provides excellent pressure maintenance (depletion virtually zero). At this stage of the well life, little further information about the reservoir can be expected from future production. The objective of the dynamic simulation of the field was to decide whether or not an additional well should be drilled to the south of the field in an apparently nondrained zone for which a three-dimensional (3D) seismic survey had shown a structural high. The uncertainty on the size of this local structural high was identified during the course of the study as being a major one. The dynamic study undertaken prior to the present work was a conventional one, performed using a structural map considered by the geophysicist as the most probable as a starting point. But satisfactory production history matching was impossible without impairing the consistency of the geological model. Structural Uncertainties After the seismic survey on the field had been interpreted, a study of the uncertainties on the structural map was decided on, in order to:determine statistically the rock volume and measure the impact of the structural uncertainties on dynamics, andmeasure the uncertainty on the structural high to the south of well P-1 so as to quantify the gains to be obtained from a new well. Geological and Geophysical Context. The field is located in a foot-hills basin. The reservoir has an overall almond shape running North-South, limited on its western flank by an extensive, normal fault (Fig. 1). The top reservoir is scarcely visible on the seismic data, and matching proved far from easy owing to static correction problems. The nature of the seismic marker corresponding to the top reservoir ranges from a zero crossing phase to a trough, between the oil zone and the reservoir flanks, rendering picking in this intermediate zone difficult. The time-to-depth conversion was carried out using two intermediate horizons. For calculating interval velocities, seismic time versus well depth regression functions were used. In the three intervals, compaction laws (V=V0+KZ) were used. In each geological unit the V0 values measured in the wells were kriged to form a map while the K coefficient was assumed to be constant. Construction of Uncertainty Maps. Only the errors in picking and depth conversion were taken into account. It was decided that the uncertainties on the preprocessing and migration could be integrated into the uncertainties on depth conversion. The map of uncertainty on picking was determined on the basis of three criteria:the difference between several interpretations,the problems of well-seismic matches, andthe amplitude map of top reservoir. To compute the uncertainty value (2 s) at each point the picking uncertainty map was constructed "by hand" but it can be seen as the root mean square of the sum of the square of the three criteria, i.e., the difference between interpretations, the well seismic mismatch and the quality maps ("inverse" of amplitude). The uncertainty thus determined is generally below 10 m except in the polarity change zone where it may exceed 30 m. Geological and Geophysical Context. The field is located in a foot-hills basin. The reservoir has an overall almond shape running North-South, limited on its western flank by an extensive, normal fault (Fig. 1). The top reservoir is scarcely visible on the seismic data, and matching proved far from easy owing to static correction problems. The nature of the seismic marker corresponding to the top reservoir ranges from a zero crossing phase to a trough, between the oil zone and the reservoir flanks, rendering picking in this intermediate zone difficult. The time-to-depth conversion was carried out using two intermediate horizons. For calculating interval velocities, seismic time versus well depth regression functions were used. In the three intervals, compaction laws (V=V0+KZ) were used. In each geological unit the V0 values measured in the wells were kriged to form a map while the K coefficient was assumed to be constant. Construction of Uncertainty Maps. Only the errors in picking and depth conversion were taken into account. It was decided that the uncertainties on the preprocessing and migration could be integrated into the uncertainties on depth conversion. The map of uncertainty on picking was determined on the basis of three criteria:the difference between several interpretations,the problems of well-seismic matches, andthe amplitude map of top reservoir. To compute the uncertainty value (2 s) at each point the picking uncertainty map was constructed "by hand" but it can be seen as the root mean square of the sum of the square of the three criteria, i.e., the difference between interpretations, the well seismic mismatch and the quality maps ("inverse" of amplitude). The uncertainty thus determined is generally below 10 m except in the polarity change zone where it may exceed 30 m.
35
Liu, Jun, Gang Yi Zhou, Xin Long Dong, and Guo Fu Li. "System Design for High Energy Rate Electromagnetic Powder Compaction Devices." Advanced Materials Research 97-101 (March 2010): 1146–49. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.1146.
Повний текст джерелаАнотація:
In this paper, the main element is constructed high energy electromagnetic compaction system on the high-energy flat coil. Physical model for analyzing dynamic response of high pulse current was reviewed. Design loading device using high energy electromagnetic technology to suppress powder, consider the exhaust, stripping, loading, positioning and other issues,propose a more reasonable program.The device includes various components of the installation. such as coil, the coil plate, driver, amplifiers, punching first, die, upper and lower fixing plate. The model of device based on Pro/E to facilitate manufacturing.Pressure embryo along the suppression direction has more uniform density distribution.The technology possesses advantagesof the single side forming and directional loading.
36
You, Dongdong, Dehui Liu, Hangjian Guan, Qingyun Huang, Zhiyu Xiao, and Chao Yang. "A Control Method of High Impact Energy and Cosimulation in Powder High-Velocity Compaction." Advances in Materials Science and Engineering 2018 (July 29, 2018): 1–11. http://dx.doi.org/10.1155/2018/9141928.
Повний текст джерелаАнотація:
To enhance the impact energy of powder high-velocity compaction (HVC) and thus improve the green density and mechanical properties of the resulting compacts, a mechanical energy storage method using combination disc springs is proposed. The high impact energy is achieved by modifying existing equipment, and the hydraulic control system is developed to implement the automatic control of the energy produced from the disc springs. An interdisciplinary cosimulation platform is established using the ADAMS, AMESim, and LabVIEW software packages to perform the interactive control of the simulation process and the real-time feedback of the simulation results. A mechanical-hydraulic cosimulation of the energy control virtual prototype of the testing machine is conducted using this platform. The influence of the impact energy on the green density is studied according to the HVC experimental results of the iron-based powders, and then, the green compact with the higher relative density is produced. The experimental results indicate that the energy enhancement method using the combination disc springs is reasonable and that the hydraulic control scheme is reliable.
37
Shi, Bin Bin, Ying Sun, Li Chen, and Jia Lu Li. "Energy Absorption of Ultra-High Molecular Weight Polyethylene Fiber-Reinforced Laminates at High Strain Rates." Applied Mechanics and Materials 34-35 (October 2010): 1532–35. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.1532.
Повний текст джерелаАнотація:
Some dynamic compressive tests about Ultra-High Molecular Weight Polyethylene Fiber-reinforced laminated Composites have been done using SHPB experimental system．The stress-strain curves of UHMWPE Fiber-reinforced Composites of three different laminated angles (0/90°, 0/90/45/-45°, 0/90/30/-60/60/-30°) are obtained at higher strain rates and their dynamic mechanical properties are also investigated at the same time．Based on all the stress-strain curves obtained, the characteristics of energy absorption of UHMWPE fiber angle-plied composites are analyzed and discussed．It is found that laminated angle has made little effect on the dynamic energy absorption of composites at higher strain rates．In addition，delamination and compaction in the thickness direction constitute the main dynamic failure mechanisms, which are studied by means of image analyses for the specimens after compression.
38
Xu, Chao, Zhong-qing Chen, Jun-shi Li, and Yuan-yuan Xiao. "Compaction of Subgrade by High-Energy Impact Rollers on an Airport Runway." Journal of Performance of Constructed Facilities 28, no. 5 (October 2014): 04014021. http://dx.doi.org/10.1061/(asce)cf.1943-5509.0000469.
Повний текст джерела
39
Kuang, Xi Long. "Testing Study and Numerical Analysis of Dynamic Compaction on the Red Sandstone Rubble Soil." Applied Mechanics and Materials 97-98 (September 2011): 151–55. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.151.
Повний текст джерелаАнотація:
The drop distance, times of dynamic compaction and other parameters are studied by on-site testing in order to analyse quantitatively the impact on effective reinforcement depth and radius of the red sandstone rubble soil. Large amounts of on-site test data shows that compactness standard is 93%, strong encryption range is 1.0～4.0m, the effective impact depth is 4～6m and the effective impact radius is 2.5～3.5m. At the same time, through comparison and verification the on-site testing data and numerical analysis, the relationship between times of dynamic compacting and sandstones subside is . Further more, it is revealed that dynamic compaction can restrain effectively the deformation of high fill embankment of the red sandstone rubble soil.
40
Wu, Bingquan, Wankui Ni, and Haiman Wang. "Stability Analysis of Loess High Slope under Dynamic Compaction Based on Matrix Discrete Element Method." Advances in Civil Engineering 2022 (December 19, 2022): 1–13. http://dx.doi.org/10.1155/2022/9089652.
Повний текст джерелаАнотація:
In order to investigate the safety and stability of loess high slope under dynamic ramming, the MatDem software was used to simulate the process of heavy rammer compacting the spot which was 11 m away from the toe of loess high slope. The rammer was applied with different energies of 10000 kN·m, 8000 kN·m, and 6000 kN·m. In this way, the safety and stability of slope under the action of different dynamic tamping energies can be determined. The results show that the loess high slope presented circular landslide damage by dynamic compaction. Under the same ramming times, with the decrease of ramming energy, the damage degree of loess high slope gradually reduced. According to the displacement value of different monitoring points, the large horizontal and vertical displacement points in landslide were obtained. When the ramming energy was 10000 kN·m and 8000 kN·m, the maximum horizontal displacements were 15.45 m and 10.72 m, and the maximum vertical displacements were 17.43 m and 11.91 m. When the ramming energy was 6000 kN·m, the soil at the bottom of slope would produce slight vibration. Considering the actual project, when the ramming energy was 10000 kN·m and 8000 kN·m, the minimum safe distance was recommended to be 25 m and 20 m. When the ramming energy was 6000 KN·m, the slope remained stable as a whole, and the minimum safe distance suggested should not be less than 11 m. A safety distance of collapse of loess high slope under dynamic compaction was determined, which provided a strong safety guidance for loess high slope construction under dynamic compaction.
41
Chen, Rong Jun, and Juan Guo. "The Test Research on Impact Compaction Reinforcement of the Soil Base." Advanced Materials Research 753-755 (August 2013): 673–77. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.673.
Повний текст джерелаАнотація:
This article verifies the feasibility to impact rolling technology instead of dynamic consolidation in soil areas soil region reinforcement processing by impact rolling soil base reinforcement experiments .In this essay, high soil areas embankment large area of reinforcement processing has opened up a new way.
42
Zhang, Jinhua, Yadong Zhang, Junyu Fan, Qin Fang, and Yuan Long. "Mesoscopic investigation of layered graded metallic foams under dynamic compaction." Advances in Structural Engineering 21, no. 14 (April 12, 2018): 2081–98. http://dx.doi.org/10.1177/1369433218766941.
Повний текст джерелаАнотація:
This article is aimed to reveal the dynamic response of layered graded metallic foam under impact loading using a three-dimensional mesoscopic model. First, a mesoscopic model for closed-cell metallic foam is proposed based on the X-ray computed tomography images. Second, a numerical analysis approach is presented and validated with test data. Third, it studies the dynamic behavior of the layered graded metallic foam under impact loading numerically. The metallic foam specimen is composed layer by layer. The porosity, which is a fraction of the voids volume over the total volume, is different with each other for the layers. Simulations are conducted to the specimen with increasing and decreasing porosity arrangement. Results show that the layer arrangement is critical to the dynamic properties. The mesoscopic deformation of cell walls and the energy absorption capability are also affected significantly. This article gives insights into the mechanical properties and mesoscopic deformation of layered graded metallic foam.
43
Sano, Yukio. "Multiple Shock Compaction of Simple Type Powders by Punch Impact." Journal of Energy Resources Technology 114, no. 2 (June 1, 1992): 117–38. http://dx.doi.org/10.1115/1.2905931.
Повний текст джерелаАнотація:
Recently, we have elucidated some mechanical behaviors of powders during the compaction. The elucidation involves the constitutive relations of a powder medium under the multishock compaction, the qualitative behavior such as the similarities of the compaction processes, the die wall friction effect, and the uniformity of the final density distribution of the compact with a high density, and the quantitative behavior analyzed by the pseudo-viscosity method and the shock fitting. This review describes this behavior systematically.
44
Bonicelli, Alessandra, Maurizio Crispino, Filippo Giustozzi, and Melanie Shink. "Laboratory Analysis for Investigating the Impact of Compaction on the Properties of Pervious Concrete Mixtures for Road Pavements." Advanced Materials Research 723 (August 2013): 409–19. http://dx.doi.org/10.4028/www.scientific.net/amr.723.409.
Повний текст джерелаАнотація:
Pervious concrete is a relatively new material, standards and rigorous specifications for construction and placement are therefore still missing. One the one hand, the main characteristic to achieve is a high permeability to allow meteoric water percolate in the pavement and evaporate from the subgrade. On the other hand, developing pavement cementitious mixtures able to retain high void contents and reach significant mechanical performance entails an in-depth analysis of materials and construction practices. Pervious concrete can indeed be placed using a standard paver as for asphalt mixtures but the compaction stage is usually demanded to the contractor practices: light steel hand-rollers or standard drum rollers are both used without an in-depth knowledge of compaction properties of the cementitious mixture. The present paper aims at investigating the influence of compaction methods on the mechanical performance and void contents of pervious concrete mixtures. Several compaction procedures were tested modifying the compaction energy and the mixture characteristics while preserving high permeability. The main objective was to simulate and identify the effect of commonly adopted in situ compaction techniques - i.e.: tamper compaction as provided by the paver, steel hand-roller compaction, or standard drum roller compaction. Results showed how the compaction energy, water/cement ratios, and the percentage of cement affect the Indirect Tensile Strength and void contents of the mixtures. Further investigations were also conducted in order to comprehensively evaluate how the variation in the percentage of cement and water/cement ratio influenced the stiffness of the material.
45
Zhu, Guang Shan, and Ling Yu. "Compaction Temperature's Influence on the Pavement Performance of Warm Asphalt Mix with Different Matrix." Applied Mechanics and Materials 405-408 (September 2013): 1806–9. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.1806.
Повний текст джерелаАнотація:
Warm mix asphalt (WMA) is a new type of asphalt mixture that uses a special additive to reduce mixing temperature and compaction temperature to realize energy saving and environmental protection purpose. Laboratory tests are conducted to study that, at different compaction temperatures, the air void rate, dynamic stability and change rule of flexural-tensile strain of the Sasobit WMA of 3 matrix asphalts (Liaohe70#, Liaohe90#, Karamay90#). The results show that when compaction temperature rises, air void rate decreases and the degree of decrease turns slow. At the same temperature, WMA of Karamay90# added with 3% of Sasobit (K90S) has the least air void rate. Along with the rising of the compaction temperature, dynamic stability increases in linearity. At the same temperature, WMA of Liaohe90# added with 3% of Sasobit (L90S) has the best dynamic stability. 115°C is the optimal compaction temperature for L70S and K90S to keep relatively high flexural-tensile strain. At the same compaction temperature, difference of flexural-tensile strain is small among 3 matrix asphalts.
46
Salini, Reus, and Carl Anders Lenngren. "HIGH AIR-VOID VOLUME IMPLICATIONS FOR ASPHALT CONCRETE SERVICE-LIFE AND PRICE PENALTY." Stavební obzor - Civil Engineering Journal 31, no. 1 (April 30, 2022): 58–65. http://dx.doi.org/10.14311/cej.2022.01.0005.
Повний текст джерелаАнотація:
In road industry, the construction of asphalt concrete layers is a dynamic process that, if not properly done, will lead to problems compromising the pavement performance. One of the most common problems is poor compaction leading to air-void volume above the maximum acceptable. This study discusses the impact of compaction/density deficiencies and presents an innovative model to calculate the asphalt pavement service-life loss in a simple and objective way, and in line with the road construction managers needs to calculate price penalty for contractors. The model was optimized for dense graded asphalt concrete, that typically has a maximum acceptable air‑void volume between 4% and 7%.
47
Lu, Aihong, Jinhai Xu, Yu Xia, and Lei Sun. "Study on Dynamic Behavior and Energy Dissipation of Rock considering Initial Damage Effect." Shock and Vibration 2021 (July 13, 2021): 1–10. http://dx.doi.org/10.1155/2021/7937459.
Повний текст джерелаАнотація:
To explore the influence of initial damage on the dynamic characteristics of rock mass, the Φ 50 mm split Hopkinson pressure bar (SHPB) test system was used, and the uniaxial impact compression tests on yellow sandstone specimens with different damage degrees were conducted, and then the variation law of mechanical properties of rock specimens with the initial damage was determined. The test results show that the dynamic stress-strain curve of rock specimens with initial damage can be roughly divided into compaction stage, elastic deformation stage, crack evolution stage, and strain-softening stage; the higher the initial damage degree of rock mass, the more significant the compaction stage. With the increase of the initial damage degree, the dynamic elastic modulus and peak stress of rock mass decrease gradually in a power number, while the peak strain of rock mass increases exponentially. With the increase of the initial damage degree, both the reflected energy ratio and the dissipated energy ratio decrease linearly, while the transmitted energy ratio increases linearly; the increasing rate of the transmitted energy ratio is greater than the decreasing rate of the reflected energy ratio.
48
Allen, Robert M., and John E. Smugeresky. "Dynamic Compaction of Rapidly Solidified Al-6%Si Powder." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 36–37. http://dx.doi.org/10.1017/s0424820100117261.
Повний текст джерелаАнотація:
The production of alloy powders by processes involving rapid solidification can yield powder particles which exhibit highly-refined microstructures desireable from a mechanical properties standpoint. Unfortunately, traditional methods for compacting powders into parts often cause significant coarsening of the starting powder microstructure. Alternative methods such as dynamic compaction (the shock-loading of the powder under high stresses) are under study as means of preserving the fine-scale of the starting microstructure throughout the manufacturing of a fully-dense bulk part.The purpose of the present work was to examine the microstructures developed by the dynamic compaction of rapidly-solidified Al-6%Si alloy powders. The powder was prepared from cast alloy using an ultrasonic gas atomizer. Particles < 250 μm in diameter were sieved to produce uniform size splits for the compaction study. Dynamic compaction was carried out with a gas gun device which imposed a shock stress of ∼4 GPa on a powder sample, producing a fully-dense compact 30 mm in diameter and 5 to 6 mm thick. Microstructural characterization was carried out using a JEOL 35CF SEM and a 200CX STEM, both equipped with energy-dispersive x-ray spectrometry systems.
49
Xie, Xianqi, Yingkang Yao, Jun Liu, Peining Li, and Gui Yang. "Mechanical Behavior of Unsaturated Soils Subjected to Impact Loading." Shock and Vibration 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/4703981.
Повний текст джерелаАнотація:
This paper presents an experimental study on unsaturated soils. A designed test setup was used and the impact loading was applied with a drop hammer. The experimental results show that the soil properties, including water content, density, void ratio, and saturation, changed because of impact loading, and these variations of the soil properties affected the matrix suctions of the unsaturated soils. The impact hole depth increased with the increasing impact energy and gradually reached a critical value. The dynamic stress in soil increased with the increased impact loading. The results obtained in this work can be applied to optimize the effective reinforcement region of soils in the dynamic compaction construction.
50
Feng, Shi-Jin, Ke Tan, and Wei-Hou Shui. "Dynamic Compaction of Ultra-High Energy in Combination with Ground Replacement in Coastal Reclamation Areas." Marine Georesources & Geotechnology 33, no. 2 (October 24, 2014): 109–21. http://dx.doi.org/10.1080/1064119x.2013.805288.
Повний текст джерела