Journal articles on the topic 'Lateral loads Testing'
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Behnamghader, Aliasghar, Reyhaneh Neghabat Shirazi, Alain Iost, and Denis Najjar. "Surface Cracking and Degradation of Dense Hydroxyapatite through Vickers Microindentation Testing." Applied Mechanics and Materials 66-68 (July 2011): 614–19. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.614.
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Surface degradation and cracking of dense hydroxyapatite were evaluated through Vickers micro indentation using indentation loads ranged from 25 gf to 2000 gf. Crack lengths, imprint diameters and the number of lateral cracks and chips were measured using SEM. The crack length-indentation load data were analyzed with regard to the specific relations of Palmqvist and fully developed radial cracks. Crack type transition load from Palmqvist to median crack was experimentally assessed through serial sectioning technique. The analytical estimated transition load, based on the theoretical relation of the indentation load and crack lengths showed a good agreement with one obtained from experimental itinerary. Palmqvist and median cracks were identified in low and medium indentation loads, respectively. High indentation load could also lead to the formation of lateral cracks and chips. The tendency for lateral cracking was evaluated taking into account the number of lateral cracks and chips. The chips were found to be appeared just after test in higher indentation load, whereas in medium loads they could be detectable only after several weeks.
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Pinto, Paulo, Michael McVay, Marc Hoit, and Peter Lai. "Centrifuge Testing of Plumb and Battered Pile Groups in Sand." Transportation Research Record: Journal of the Transportation Research Board 1569, no. 1 (January 1997): 8–16. http://dx.doi.org/10.3141/1569-02.
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Pile groups are generally used under structures subject to heavy axial loads or large lateral forces with or without scour. The focus in this paper is only on pile groups subject to large lateral forces. Currently, little, if any, full-scale lateral load data exist on pile groups that vary pile head fixity or batter. Reported here is the summary of a series of centrifuge tests on free- and fixed-head plumb and battered pile groups. Influence of pile head constraint, pile spacing, soil density, and vertical dead load is reported for groups ranging from 3 × 3 to 3 × 7 in size. Results reveal a significant lateral resistance of fixed- over free-head pile groups; fixed-head piles develop significant axial forces; battered piles without vertical dead loads are generally no better than plumb piles; and in the case of plumb piles, the use of multipliers to represent group interaction is valid.
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Buttermann, G. R., R. D. Kahmann, J. L. Lewis, and D. S. Bradford. "An Experimental Method for Measuring Force on the Spinal Facet Joint: Description and Application of the Method." Journal of Biomechanical Engineering 113, no. 4 (November 1, 1991): 375–86. http://dx.doi.org/10.1115/1.2895415.
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A technique is described for measuring load magnitude and resultant load contact location in the facet joint in response to applied loads and moments, and the technique applied to the canine lumbar spine motion segment. Due to the cantilever beam geometry of the cranial articular process, facet joint loads result in surface strains on the lateral aspect of the cranial articular process. Strains were quantified by four strain gages cemented to the bony surface of the process. Strain measured at any one gage depended on the loading site on the articular surface of the caudal facet and on the magnitude of the facet load. Determination of facet loads during in vitro motion segment testing required calibration of the strains to known loads of various magnitudes applied to multiple sites on the caudal facet. The technique is described in detail, including placement of the strain gages. There is good repeatability of strains to applied facet loads and the strains appear independent of load distribution area. Error in the technique depends on the location of the applied facet loads, but is only significant in nonphysiologic locations. The technique was validated by two independent methods in axial torsion. Application of the technique to five in vitro canine L2–3 motion segments testing resulted in facet loads (in newtons, N) of 74 + / −23 N (mean + /−STD) in 2 newton-meter, Nm, extension, to unloaded in flexion. Lateral bending resulted in loads in the right facet of 40 + /− 32 N for 1 Nm right lateral bending and 54 + / − 29 N for 1 Nm left lateral bending. 4 Nm Torsion with and without 100 N axial compression resulted in facet loads of 92 + / − 27 N and 69 + / − 19 N, respectively. The technique is applicable to dynamic and in vivo studies.
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LaMothe, Jeremy M., Josh R. Baxter, Sydney C. Karnovsky, Conor I. Murphy, Susannah Gilbert, and Mark C. Drakos. "Syndesmotic Injury Assessment With Lateral Imaging During Stress Testing in a Cadaveric Model." Foot & Ankle International 39, no. 4 (December 21, 2017): 479–84. http://dx.doi.org/10.1177/1071100717745660.
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Background: External rotation, lateral, and sagittal stress tests are commonly used to diagnose syndesmotic injuries, but their efficacy remains unclear. The purpose of this study was to characterize applied stresses with fibular motion throughout the syndesmotic injury spectrum. We hypothesized that sagittal fibular motion would have greater fidelity in detecting changes in syndesmotic status compared to mortise imaging. Methods: Syndesmotic instability was characterized using motion analysis during external rotation, lateral, and sagittal stress tests on cadaveric specimens (n = 9). A progressive syndesmotic injury was created by sectioning the tibiofibular and deltoid ligaments. Applied loads and fibular motion were synchronously measured using a force transducer and motion capture, respectively, while mortise and lateral radiographs were acquired to quantify clinical measurements. Fibular motion in response to these 3 stress tests was compared between the intact, complete lateral syndesmotic injury and lateral injury plus a completely sectioned deltoid condition. Results: Stress tests performed under lateral imaging detected syndesmotic injuries with greater sensitivity than the clinical-standard mortise view. Lateral imaging was twice as sensitive to applied loads as mortise view imaging. Specifically, half as much linear force generated 2 mm of detectable syndesmotic motion. In addition, fibular motion increased linearly in response to sagittal stresses (Pearson’s r [ρ] = 0.91 ± 0.1) but not lateral stresses (ρ = 0.29 ± 0.66). Conclusion: Stress tests using lateral imaging detected syndesmotic injuries with greater sensitivity than a typical mortise view. In addition to greater diagnostic sensitivity, reduced loads were required to detect injuries. Clinical Relevance: Syndesmotic injuries may be better diagnosed using stress tests that are assessed using lateral imaging than standard mortise view imaging.
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Zlobina, Irina V. "Fiberglass: Lateral Loads from Climatic and Temporary Factors." Materials Science Forum 1031 (May 2021): 88–96. http://dx.doi.org/10.4028/www.scientific.net/msf.1031.88.
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The influence of modification of fiberglass in the cured state in the microwave electromagnetic field on the value of the limit stresses is significantly manifested when testing samples in the initial state. The increase in limit voltages is on average 7%. Tests of modified samples after exposure in full-scale conditions showed a decrease in the effect with an increase in the exposure time from 6% for exposure of 3 months to 3% for exposure of 8 months. This significantly increases the uniformity of the bending strength values in the batch, which is manifested in a decrease in the coefficient of variation of limit stresses relative to the control samples by 33%. Functional dependencies in the form of 2nd-order polynomials are obtained, which allow predicting the stability of products made of modified fiberglass for long-term operation under the influence of environmental factors with a confidence of up to 98%.
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Silva, P. F., and F. Seible. "EXPERIMENTAL PROCEDURE FOR TESTING OF PILES UNDER VARYING AXIAL AND LATERAL LOADS." Experimental Techniques 25, no. 1 (January 2001): 25–29. http://dx.doi.org/10.1111/j.1747-1567.2001.tb00004.x.
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Ting, John M., Claudia R. Kauffman, and Maryann Lovicsek. "Centrifuge static and dynamic lateral pile behaviour." Canadian Geotechnical Journal 24, no. 2 (May 1, 1987): 198–207. http://dx.doi.org/10.1139/t87-025.
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The behaviour of a single vertical pile embedded in saturated sand and subjected to cyclic static and dynamic loading is studied using an extensive centrifuge model testing program. A reliable data reduction method allows computation of the dynamic and static cyclic lateral pile resistance–deflection p–y curves. The results are compared with full-scale dynamic test results and oil industry design guidelines.From these comparisons, the centrifuge technique appears to model the dynamic soil–pile system properly. For loadings causing significant nonlinearity, the static stiffness appears to be greater than the dynamic stiffness, while material hysteresis appears about the same in each case. Current American Petroleum Institute guidelines for static cyclic loading appear to overestimate the dynamic lateral resistance for medium dense sands. Key words: centrifuge model, cyclic loads, dynamic response, lateral loads, liquefaction, model tests, pile lateral loads.
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Georgiadis, M., C. Anagnostopoulos, and S. Saflekou. "Centrifugal testing of laterally loaded piles in sand." Canadian Geotechnical Journal 29, no. 2 (April 1, 1992): 208–16. http://dx.doi.org/10.1139/t92-024.
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Results of an investigation of the response of piles in sand, under lateral loads, are presented. Model piles of three different diameters and flexural stiffnesses were tested in a centrifuge apparatus to determine prototype pile behavior. The experimental results, consisting of pile head displacements and bending moment distributions along the pile length, were interpreted, analyzed, and compared with the results of several numerical analyses. The piles were treated as elastic beams on nonlinear springs, examining several different types of soil reaction relationship (p-y curves). A new p-y relationship was developed for piles in cohesionless soil which provided very satisfactory results. Key words : pile, sand, lateral loading, centrifuge, numerical analysis.
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Tanjung, Jafril, and Maidiawati. "Cyclic behavior of the R/C frames with reinforced masonry infills." E3S Web of Conferences 156 (2020): 05014. http://dx.doi.org/10.1051/e3sconf/202015605014.
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This study focuses on the experimental works to define the behavior of the reinforced concrete (R/C) frame model with the strengthening of the brick masonry infill by using the embedded reinforcement bars subjected to lateral reversed cyclic loads. A previous study by applying the lateral monotonic static loads showed that the embedded reinforcement bars increased the lateral capacity of the R/C frame and also delayed the failure of the brick masonry infill and R/C frame structure as well. However, in order to define its seismic capacity, a lateral reversed cyclic loading is required. The experimental works in this study were conducted by preparing and testing the 1/4 scaled-down R/C frame specimens represented the first story of the middle multi-story commonly constructed in the earthquake-prone area such as West Sumatera, Indonesia. The R/C frame specimens were two R/C frames with brick masonry infills where one of them strengthened by the embedded reinforced bars. All specimens were tested for applying the lateral reversed cyclic loads. The applied lateral load, the lateral displacement, the progressive cracks, and the failure mode of the specimens were observed and recorded during experimental works. As it was expected, the presence of the embedded reinforced bars in the brick masonry infills increases the seismic capacity and stiffness of the R/C specimens and also delayed the failure of the specimens. The experimental results in this study imply the simple strengthening method for the brick masonry infills.
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Coronelli, Dario, Marco Lamperti Tornaghi, Luca Martinelli, Francisco-Javier Molina, Aurelio Muttoni, Ion Radu Pascu, Pierre Pegon, et al. "Testing of a full-scale flat slab building for gravity and lateral loads." Engineering Structures 243 (September 2021): 112551. http://dx.doi.org/10.1016/j.engstruct.2021.112551.
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Wang, Qing Xiang, Gang Wang, and Zhong Jun Li. "Experiment Study on Compressive Membrane Action of Slab Strips Restrained by Shear Walls." Key Engineering Materials 417-418 (October 2009): 805–8. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.805.
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Subjecting to the compressive membrane action (CMA), the ultimate load capacity of the reinforced concrete (RC) slab with lateral restraint would be improved obviously. Test of 12 one-way slab specimens restrained by shear-walls was carried out to investigate the properties of the slab strips’ compressive membrane action. The reduced-size specimens were designed to keep the ratios of shear-walls’ restraint stiffness to slab strips’ flexural stiffness unchanged. One horizontal testing instrument was first used to record the development of the slabs’ lateral restraint forces. The ultimate loads of slab strips with certain lateral restraint stiffness gave an average 38.3% rise from the calculations of upper-bound method. Though the increment of slab’s ultimate load was due to the additional moment formed by the lateral restraint force, the results showed that the peak of lateral force lagged of the slab strips’ ultimate load, which was different from the previous hypothesis. Various parameters which affect the development of CMA were also investigated, such as the shear-wall’s thickness, axial load on the walls, the slab strips’ span-height ratio and reinforcement percentage.
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Novaretti, João V., Jayson Lian, Andrew J. Sheean, Calvin K. Chan, Joon H. Wang, Moises Cohen, Richard E. Debski, and Volker Musahl. "Lateral Meniscal Allograft Transplantation With Bone Block and Suture-Only Techniques Partially Restores Knee Kinematics and Forces." American Journal of Sports Medicine 47, no. 10 (June 28, 2019): 2427–36. http://dx.doi.org/10.1177/0363546519858085.
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Background: The ability of lateral meniscal allograft transplantation (MAT) to improve knee stability and the meniscal load-bearing function in patients after meniscectomy is critical for surgical success. Purpose: To compare the effects of 2 lateral MAT fixation techniques—bone block and suture only—on knee kinematics and forces. Study Design: Controlled laboratory study. Methods: With a robotic testing system, loads were applied during flexion on 10 fresh-frozen cadaveric knees: 134-N anterior tibial load + 200-N axial compression, 5-N·m internal tibial + 5-N·m valgus torques, and 5-N·m external tibial + 5-N·m valgus torques. Kinematic data were recorded for 4 knee states: intact, total lateral meniscectomy, lateral MAT bone block, and lateral MAT suture-only fixation. In situ force in the anterior cruciate ligament and resultant forces in the lateral meniscus and in the meniscal allograft were quantified via the principle of superposition. A repeated measures analysis of variance was used to analyze variations in kinematics and forces at 0°, 30°, 60°, and 90° of knee flexion. Significance was set at P < .05. Results: When anterior loads were applied, a decrease in medial translation of the tibia that was increased after total lateral meniscectomy was observed at 30°, 60°, and 90° of knee flexion for both the lateral MAT bone block (54.2%, 48.0%, and 50.0%) and the MAT suture-only (50.0%, 40.0%, and 34.6%) fixation techniques ( P < .05). Yet, most of the increases in knee kinematics after lateral meniscectomy were not significantly reduced by either lateral MAT technique ( P > .05 for each MAT technique vs the total lateral meniscectomy state). Resultant forces in the meniscal allograft were 50% to 60% of the resultant forces in the intact lateral meniscus in response to all loading conditions at all flexion angles ( P < .05). Overall, no significant differences between lateral MAT techniques were observed regarding kinematics and forces ( P > .05). Conclusion: Lateral MAT partially restored medial translation of the tibia, and the resultant forces in the meniscal allograft were only 50% to 60% of the intact lateral meniscus forces in the cadaver model. In the majority of testing conditions, no significant changes of the in situ force in the anterior cruciate ligament were observed. Surgeons should consider the potential benefits of lateral MAT when deciding the appropriate treatment for symptomatic patients after lateral meniscectomies. Both lateral MAT techniques functioned similarly. Clinical Relevance: The load-bearing function of the meniscal allograft observed in this study may be beneficial in ameliorating the short- and long-term disability associated with lateral meniscal deficiency.
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Chigullapally, Pavan, Lucas Hogan, Liam Wotherspoon, Max Stephens, and Michael Pender. "Experimental and numerical analysis of the lateral response of full-scale bridge piers." Bulletin of the New Zealand Society for Earthquake Engineering 55, no. 2 (May 31, 2022): 95–111. http://dx.doi.org/10.5459/bnzsee.55.2.95-111.
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This paper presents the results of in-situ testing of two integrated pile-columns of a partially demolished bridge located in Auckland, New Zealand. A series of tests involving lateral monotonic pushover and subsequent dynamic free vibration snapback tests were used to quantify the variation in the stiffness and damping behaviour of the pile-column specimens over a range of lateral load levels. Each testing sequence consisted of incrementally increasing peak monotonic loads followed by the dynamic snapback, with a series of varying peak loads at the end of the testing sequence to evaluate the influence of loading history on the monotonic and dynamic response. The secant stiffness between the monotonic pushover tests performed to the same loading levels before and after the maximum load was applied, reduced by up to 40% in both the pile-columns, primarily due to soil gapping effects, highlighting the significant potential softening of the system prior to pile or column yielding. Progressive reduction in the damping of the system during each snapback test was evident, due to the varying contributions of different energy dissipation mechanisms, and the level of damping varied depending on the peak load applied. These results highlighted the significant influence of soil gapping and nonlinearity on the dynamic response of the system. Numerical models were developed in the open source structural analysis software OpenSeesPy using a Nonlinear Beam on Winkler Foundation approach to further investigate the response of the pile-columns. Models of both the pile-columns using existing p-y curves for clay soils showed good agreement with the experimental data in load-displacement, period and snapback acceleration time histories. Sensitivity analysis showed that the surface soft clay layer had a significant effect on the lateral response and dynamic characteristics of the model, reinforcing the need for good characterisation of the near surface soil profile to capture the behaviour of the system.
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Yuan, Yongquan, Minghua Zhao, Yao Xiao, and Chaowei Yang. "Model Testing of Encased Stone Column Composite Foundations under Traffic Loads." Advances in Civil Engineering 2021 (August 6, 2021): 1–11. http://dx.doi.org/10.1155/2021/6675176.
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In soft soil foundations, geogrid encased stone column composite foundation technology has been widely applied and developed in recent years due to its efficient treatment. In this study, eight groups of laboratory model tests were performed in a large-scale testing tank to investigate the bearing mechanism and stress characteristics of the composite foundation of geogrid encased stone columns under traffic loads with different cyclic load ratios. The stress at the bottom of the stone column and settlement of the composite foundation were measured and analysed. The test results show that cyclic shearing will cause the rearrangement of the soil particles at the column-soil interface, which will cause changes in the face pressure and effective stress state of the column-soil boundary. The cyclic load has a substantial influence on the accumulation settlement of the composite foundation and the development of the lateral stress state of the column. Based on the test results, the development law of the cumulative settlement is summarized, and the change mechanism of the column stress state is analysed and discussed.
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Schmid, Ben L., Richard J. Nielsen, and Robert R. Linderman. "Narrow Plywood Shear Panels." Earthquake Spectra 10, no. 3 (August 1994): 569–88. http://dx.doi.org/10.1193/1.1585789.
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The Uniform Building Code allows plywood sheathed narrow shear panels having a height-to-width ratio of 3.5-to-one (UBC Table 25-I) to be used as lateral force resisting elements. Previous laboratory testing has concentrated on panels having a height-to-width ratio of one-to-one. This paper presents some results from the testing of plywood shear panels with a height-to-width ratio of two-to-one. Three panels were tested; each was configured to model a different construction scenario. The panels were subjected to fully reversed cyclic pseudo-static loads. Comparison of the results from the three panels indicate that the tie-down anchors must be installed with careful attention to bolt tightening sequence and torque in order to better resist lateral displacements in an earthquake. Vertical dead loads were found to reduce uplift of the panel which, in turn, reduces lateral displacements resulting from panel rotation. Decreased shear values for plywood shear walls subjected to cyclic loading and additional decreased shear values for walls with a height-to-width ratio of two-to-one are recommended.
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Kaltakcı, M. Y., A. Köken, and H. H. Korkmaz. "Analytical solutions using the equivalent strut tie method of infilled steel frames and experimental verification." Canadian Journal of Civil Engineering 33, no. 5 (May 1, 2006): 632–38. http://dx.doi.org/10.1139/l06-004.
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Frame systems are commonly used in structural design. Beams and columns are essential in the design and analysis of these types of structures. Since no practical and generally recognized method has yet been developed to determine the failure loads of these systems, nonstructural components such as architectural walls are not usually taken into consideration in the analyses. In this study, the experimental failure loads and failure types of 30 partially or fully infilled steel frame systems were determined after testing these systems under reversed cyclic horizontal loading. After the analytical study was carried out, the failure loads and failure modes of the samples were obtained analytically using the equivalent strut tie method, and experimental and analytical results were compared.Key words: infilled steel frames, partially infilled frames, lateral load-carrying capacity, equivalent strut tie method.
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Zheng, Gang, Ji-bin Sun, Tian-qi Zhang, Yang Jiao, and Yu Diao. "Centrifuge model testing to ascertain vertical displacements of a pile under cyclic lateral loads." Journal of Zhejiang University-SCIENCE A 22, no. 9 (September 2021): 760–66. http://dx.doi.org/10.1631/jzus.a2000477.
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Chen, Wen Feng, Xiao Hui Yuan, and Bin Li. "Experimental Study on Seismic Performance of AAS-CFST Column." Applied Mechanics and Materials 670-671 (October 2014): 344–48. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.344.
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Three model specimens of alkali-activated slag concrete filled steel tube (AAS-CFST) with different axial compression ratio and steel ratio were designed and tested in the present study. The seismic performance of the structures were evaluated by testing them with combined lateral constant compression and vertical cyclic loads. The structural performance, such as the testing observations, hysteretic behavior, skeleton curve, stiffness degradation, energy dissipation capacity and ductility performance was discussed in detailed. The results show that all the specimens’ damage were bending deformation mode, and the hysteretic curves are relatively smooth. Test data indicated that increased the axial compression ratio improved the load bearing capacity, initial stiffness.
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GODZHAEV, Z. A., V. V. SHEKHOVTSOV, M. V. LIASHENKO, A. I. ISKALIEV, and P. V. POTAPOV. "TEST STAND FOR VIBRATION ISOLATORS OF VEHICLE CABIN SUSPENSION." Fundamental and Applied Problems of Engineering and Technology, no. 5 (2021): 165–73. http://dx.doi.org/10.33979/2073-7408-2021-349-5-165-173.
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Modern vehicles includes a cabin suspension that provides reducing of amplitudes of vibration impacts on the cabin and if possible absorption of vibration energy portion. The cabin suspension includes vibration isolators which have various constructions and operation principles: mechanical, hydraulic, pneumatic and combined mechanisms. Stand tests provides evaluation of vibration isolators ability to reduce amplitudes of impacts on the cabin from the vehicle frame down to a necessary level during normative lifetime. This paper presents the description of the tests stand for life tests of a vehicle cabin suspension created in VSTU. Vibration isolators of a vehicles cabin suspension are impacted by loads from vertical, longitudinal– and lateral–angular cabin vibrations during exploitation. At this all load impacts have various amplitudes and time profiles. Proposed test stand provides reproduction of operational load regimes for vibration isolators testing by scheme of the loading device. This device consists of three controlled electric motors which are oriented in vertical, longitudinal and lateral axial directions and cam eccentrics mounted on motors shafts. These eccentrics may have different or similar profiles and provides impact on the loading platform. So it is possible to reproduce operational loads from vertical, longitudinal– and lateral–angular cabin vibrations on tested vibration isolators at that vibrations may have various amplitudes, frequencies and time profiles for every load impact to increase reliability of the test results.
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Liao, Fei-Yu, Wei-Jie Zhang, and Hao Han. "Cyclic performance of circular concrete-filled steel tubular members with initial gap between tube and concrete core." Advances in Structural Engineering 23, no. 1 (August 6, 2019): 174–89. http://dx.doi.org/10.1177/1369433219866291.
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It is common that initial gaps exist between the steel tube and the core concrete in concrete-filled steel tubular structural members, which might affect the performance of the structure. This article aims to study the effects of the gaps on the cyclic behaviour of circular concrete-filled steel tubular members. A total of 24 concrete-filled steel tubular specimens were tested under constant axial load and cyclically lateral loads, where the main testing parameters included the types of gap, the gap ratio, the axial load level and the steel ratio. The failure mode, lateral load versus lateral displacement hysteretic curve and load versus displacement envelope curve of concrete-filled steel tubular specimens with pre-designed gaps were experimentally investigated and compared with those of the reference ones without any gap. The effects of gaps on the ultimate strength, ductility and dissipated energy of the concrete-filled steel tubular members were quantitatively evaluated according to the test results. The influence of gaps on circular concrete-filled steel tubes under different loading conditions, such as axial compressive loading, pure bending, eccentrically compressive loading and cyclic lateral loading, was also compared and discussed.
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Fleming, Bradley J., Sri Sritharan, Gerald A. Miller, and Kanthasamy K. Muraleetharan. "Full-Scale Seismic Testing of Piles in Improved and Unimproved Soft Clay." Earthquake Spectra 32, no. 1 (February 2016): 239–65. http://dx.doi.org/10.1193/012714eqs018m.
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A full-scale field investigation was performed to determine the effects of soil improvement on the seismic resistance of piles in soft clay. A soil improvement method, called cement deep soil mixing (CDSM), was used to improve soil supporting a standard 324 mm diameter steel pipe pile subjected to simulated earthquake lateral loads. An identical pile in unimproved clay was also tested to determine the effects of the soil improvement. Compared to the unimproved pile, the CDSM technique showed a 42% increase in pile lateral strength, a 600% increase in effective elastic stiffness, and a 650% increase in average equivalent damping ratio. The pile in improved soil reached its lateral capacity at a head displacement of 0.1 m, at which point the critical region at the base of the pile above the improved ground experienced buckling and subsequent fracture due to low cycle fatigue.
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Zhao, Dongfu, Haijing Gao, Huixuan Liu, Penghe Jia, and Jianhui Yang. "Fatigue Properties of Plain Concrete under Triaxial Tension-Compression-Compression Cyclic Loading." Shock and Vibration 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/9351820.
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Fatigue tests were performed on plain concrete under triaxial tension-compression-compression (T-C-C) cyclic loading with constant and variable amplitude using a large multiaxial machine. Experimental results show that, under constant amplitude fatigue loads, the development of residual strain in the fatigue loading direction depends mostly on the lateral compressive stress ratio and is nearly independent of stress level. Under variable amplitude fatigue loads, the fatigue residual strain is related to the relative fatigue cycle and lateral compressive stress ratio but has little relationship with the loading process. To model this system, the relative residual strain was defined as the damage variant. Damage evolutions for plain concrete were established. In addition, fatigue damage analysis and predictions of fatigue remaining life were conducted. This work provides a reference for multistage fatigue testing and fatigue damage evaluation of plain concrete under multiaxial loads.
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Li, Meng, Jixiong Zhang, Baifu An, Deon Germain, and Qianqian Xu. "Effect of Cyclic Lateral Loading on the Compaction Behaviour of Waste Rock Backfill Materials in Coal Mines." Energies 12, no. 1 (December 21, 2018): 17. http://dx.doi.org/10.3390/en12010017.
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Crushed waste rock (CWR) can be used as backfill for goafs allowing disposal of solid waste and control of surface subsidence. Waste rocks for backfilling (WRBs) have a certain density before use if cyclic lateral loads are applied to CWRs, therefore, by employing a self-designed bidirectional loading test system for granular materials, the influence of the number of lateral loading cycles on the compaction characteristics of WRBs was explored. Through testing, changes in mechanical parameters of WRBs during lateral and axial loading were attained to analyse the influence of lateral loading on lateral strain, axial strain, porosity, and lateral pressure coefficient during their compaction. The test results showed that: (1) the lateral loading exerted a significant influence on the porosity, strain, and lateral pressure coefficient of crushed WRBs during lateral and axial loading; (2) under lateral load, the more cycles of lateral loading applied, the greater the lateral strain and the reduction in lateral porosity of samples; (3) during axial loading, for samples subjected to multiple cycles of lateral loading, owing to the porosity of WRBs having been decreased in advance to improve their density, the final axial strain was low; (4) after compaction, the particle size distributions of CWR samples after different numbers of cycles (1, 3, 5 and 7) of lateral loading all shifted upwards compared with those obtained before compaction, implying that rock particles were crushed. However, the number of cycles of lateral load did not affect crushing of particles before, and after, compaction.
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Mitchell, M. R., R. E. Link, M. Suneel Kumar, P. Alagusundaramoorthy, and R. Sundaravadivelu. "A Novel Setup for Testing of Ship Deck Stiffened Panels under Axial and Lateral Loads." Journal of Testing and Evaluation 37, no. 2 (2009): 101923. http://dx.doi.org/10.1520/jte101923.
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Cutting, E. D., M. P. F. Sutcliffe, S. J. Langley-Hobbs, and A. M. Wallace. "A biomechanical comparison of six different double loop configurations for use in the lateral fabella suture technique." Veterinary and Comparative Orthopaedics and Traumatology 21, no. 05 (2008): 391–99. http://dx.doi.org/10.3415/vcot-07-10-0095.
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SummarySix different double loop configurations which could be applied to the lateral fabella suture (LFS) technique were subjected to in vitro mechanical testing. Three double loop, single strand and three double loop, double strand configurations were tested. The strongest configuration, with a significantly higher mean ultimate load and load at yield, was the interlocking loop configuration. This is a novel configuration which has not previously been reported. The three double loop, single strand configurations all had higher mean ultimate loads than the double loop, double strand configurations. The double strand group with uneven loop length performed very poorly, with significantly lower mean stiffness and ultimate load than all of the single strand groups. This group also developed unacceptably high levels of elongation during high level cyclic loading.
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Shenoy, Vivek N., Hanson S. Gifford, and John T. Kao. "A Novel Implant System for Unloading the Medial Compartment of the Knee by Lateral Displacement of the Iliotibial Band." Orthopaedic Journal of Sports Medicine 5, no. 3 (March 1, 2017): 232596711769361. http://dx.doi.org/10.1177/2325967117693614.
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Background: Medial knee osteoarthritis (OA) typically occurs with excessive mechanical load within the medial compartment, resulting in degeneration of the articular cartilage. Purpose: A novel extracapsular implant (Latella Knee Implant) has been developed to unload the medial compartment of the knee. The implant displaces the iliotibial band (ITB) over the lateral femoral condyle, thereby increasing its effective moment arm, resulting in a transfer of load from the medial compartment to the lateral compartment of the knee. A cadaveric study was performed to evaluate the effect of altering the moment arm of the ITB on knee biomechanics. Study Design: Controlled laboratory study. Methods: A 6-degrees-of-freedom robotic testing system was utilized to measure medial and lateral compartment loads in 8 fresh-frozen cadaveric knees at various ITB loads and knee flexion angles. Measurements were made with and without the implant in place. The system measured the compartment forces at flexion angles between 0° and 30° under 3 simulated loading conditions (300 N quadriceps, 100 N hamstrings, and [1] 0 N ITB, [2] 50 N ITB, [3] 100 N ITB). Results: Lateral displacement of the ITB between 15 and 20 mm resulted in medial compartment unloading between 34% and 65%. Conclusion: Unloading the medial compartment with this novel implant has the potential to address the treatment gap for patients with medial knee OA. Clinical Relevance: Currently, there exists a treatment gap for patients with medial compartment OA who have exhausted conservative management but whose disease and symptoms do not warrant more invasive surgical procedures. An extracapsular implant to unload the medial compartment could fill this treatment gap by providing patients and surgeons with a less invasive option for early to mid-stage OA. Unloading the medial compartment may alleviate pain and improve function, allowing patients with early-stage medial OA to remain active longer prior to considering more invasive options such as arthroplasty.
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Evseev, Kirill, Alexey Dyakov, and Roman Pashkovskiy. "Experimental research of motor vehicles on a test bench." MATEC Web of Conferences 329 (2020): 01023. http://dx.doi.org/10.1051/matecconf/202032901023.
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The article presents one of the possible methods for testing wheeled, tracked movers and support skis. The drag coefficient values of lateral tire deflection are obtained using a test bench and measuring equipment. Atmospheric and road conditions are taken into account. The tests can be carried out at various loads and velocities.
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Abbas, Jinan Laftah, and Abbas A. Allawi. "Experimental and Numerical Investigations of Composite Concrete–Steel Plate Shear Walls Subjected to Axial Load." Civil Engineering Journal 5, no. 11 (November 1, 2019): 2402–22. http://dx.doi.org/10.28991/cej-2019-03091420.
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This research is presented experimental and numerical investigations of composite concrete-steel plate shear walls under axial loads to predicate the effect of both concrete compressive strength and aspect ratio of the wall on the axial capacity, lateral displacement and axial shortening of the walls. The experimental program includes casting and testing two groups of walls with various aspect ratios. The first group with aspect ratio H/L=1.667 and the second group with aspect ratio H/L=2. Each group consists of three composite concrete -steel plate wall with three targets of cube compressive strength of values 39, 54.75 and 63.3 MPa. The tests result obtained that the increase in concrete compressive strength results in increasing the ultimate axial load capacity of the wall. Thus, the failure load, the corresponding lateral displacement and the axial shortening increased by increasing the compressive strength and the rate of increase in failure load of the tested walls was about (34.5% , 23.1%) as compressive strength increased from 39 to 63.3 MPa for case of composite wall with aspect ratio H/L=1.667 and H/L=2, respectively. The effect of increasing aspect ratio on the axial load capacity, lateral displacement and axial shortening of the walls was also studied in this study. Compared the main performance characteristic of the testing walls, it can be indicated that the walls with aspect ratio equal to (2) failed under lower axial loads as compared with walls with aspect ratio equal to 1.667 ratios by about (5.8, 12, 15.6 %) at compressive strength (39, 54.75, 63.3 MPa), respectively and experienced large flexural deformations. The mode of failure of all walls was characterized by buckling of steel plates as well as cracking and crushing of concrete in the most compressive zone. Nonlinear three-dimensional finite element analysis is also used to evaluate the performance of the composite wall, by using ABAQUS computer Program (version 6.13). Finite element results were compared with experimental results. The comparison shows good accuracy.
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Shuai, Chang-geng, Bu-yun Li, Jian-guo Ma, and Zhao-hao Yang. "A Novel Low Stiffness Air Spring Vibration-Isolation Mounting System." Shock and Vibration 2022 (February 21, 2022): 1–11. http://dx.doi.org/10.1155/2022/5598689.
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Quasi-zero-stiffness (QZS) structures offer substantial practical benefits for facilitating the essential support and isolation of vibrational source loads aboard modern marine vessels. In order to design a compact QZS system of high bearing capacity, the article proposes a low stiffness air spring (LSAS) vibration-isolation mounting system composed of both vertical and lateral air springs. The vertical air springs support the load and isolate vibrations in the vertical direction, while the lateral air springs support the load and isolate transversal vibrations. Theoretical analyses based on a simple two-dimensional, single degree of freedom model demonstrate that the proposed novel LSAS design decreases the degree of stiffness in the support structure that would otherwise be induced by introducing lateral air springs and accordingly increases the vibration isolation effect. Moreover, optimization of the air spring parameters enables the lateral air springs to provide negative stiffness and thereby realize QZS characteristics. Experimental testing based on prototypes of a standard air spring mounting system and the proposed LSAS mounting system demonstrates that the stiffness of the proposed system is about 1/5 that of the standard system. Accordingly, the proposed structure design successfully alleviates the undesirable influence of lateral air springs on the stiffness of the mounting system.
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Hamilton, H. R., John McBride, and Joseph Grill. "Cyclic Testing of Rammed-Earth Walls Containing Post-tensioned Reinforcement." Earthquake Spectra 22, no. 4 (November 2006): 937–59. http://dx.doi.org/10.1193/1.2358382.
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Rammed-earth walls are generally constructed by hand-compacting (or mechanically) a moist, soil-cement mixture into forms. These walls, when constructed in seismically active areas, require the use of steel reinforcement. The installation of steel reinforcement during rammed-earth construction can be difficult logistically. In particular, vertical reinforcing bars are difficult to place and to reach proper compaction of the surrounding rammed earth. To evaluate the use of post-tensioned reinforcement in lieu of bonded mild steel, eight full-scale rammed-earth walls were constructed and tested in out-of-plane and in-plane bending. The loads were cyclic and fully reversed to determine the ability of the walls to undergo large displacements that might accompany an earthquake. The out-of-plane tests were conducted with the specimen supported as a cantilever and the lateral load applied to the top of the wall. The specimens in the in-plane tests were also supported as a cantilever with the top unrestrained.
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Ross, Andrew S., Ashraf A. El Damatty, and Ayman M. El Ansary. "Reduced Equivalent Static Wind Loads for Tall Buildings with Tuned Liquid Dampers." Applied Mechanics and Materials 226-228 (November 2012): 1218–27. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.1218.
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The tuned liquid damper (TLD) is a proven and an increasingly popular auxiliary device for mitigating the dynamic effects induced by wind loading on tall buildings. As buildings become taller, lighter, and more flexible, there is a greater contribution from the dynamic component. The most reliable tool for assessing the dynamic component is wind tunnel testing. A boundary layer wind tunnel is capable of accurately calculating an equivalent static wind load (ESWL) acting on a building. The current study investigates the reduction in the ESWL of a lateral-torsional coupled building with a TLD system installed. The building is sensitive to torsion in the first two vibration modes. The current investigation uses three unique multi-modal TLD systems designed specifically for a lateral-torsional coupled building. The building ESWL is evaluated with the TLD systems using measurements from tests conducted at the Boundary Layer Wind Tunnel Laboratory at Western University.
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Kershaw, Kyle A., and Ronaldo Luna. "Full-Scale Field Testing of Micropiles in Stiff Clay Subjected to Combined Axial and Lateral Loads." Journal of Geotechnical and Geoenvironmental Engineering 140, no. 1 (January 2014): 255–61. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0000968.
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Andrade Pardo, Sofía, Fabián Lamus Báez, and Nancy Torres Castellanos. "Connection between a Column and its Foundation for Guadua Angustifolia Structures under Lateral Loads." Key Engineering Materials 668 (October 2015): 227–37. http://dx.doi.org/10.4028/www.scientific.net/kem.668.227.
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In Colombia, as in other developing regions, social housing shortage related problems has led local authorities to propose low cost housing projects that allow its quickly and easy construction. Among the requirements of this type of construction are solicitations for vertical and lateral loads caused by wind or earthquake forces, as well as the sustainable use of natural resources Considering this, the use of Guadua angustifolia Kunth (Guadua a.) as a structural material has awaken a great interest, considering its renewability, high-speed growth, ecological benefits and because is easily obtainable all across the country. Due to the lack of additional information, structural joints in this type of materials, are usually pinned, assuming that there is no moment transmission between the different elements, however, some types of connections can partially restrict the rotation in the supports. Additionally, the degree of constrain that any support can provide to the column is a variable that has not been studied enough, despite being essential for modeling and structural design.In this work a connection between a column of Guadua a. and its foundation was studied. The influence of each component on the connection behavior under horizontal loads was assessed, testing seven different configurations. Monotonic and dynamic testing of connections as well as the characterization of the materials used in its construction were included in the experimental schedule. It was determined that the presence of mortar grouting together with the use of longitudinal bolts slightly increases the connection strength as drastically reduce its ductility. The use of transversal bolts is the best alternative to obtain a strong, stiff and ductile connection, especially when are combined with the use of hoops.
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de Villiers, Danielle, and Simon Collins. "Resistance of a novel ceramic acetabular cup to critical impact loads." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 234, no. 10 (July 7, 2020): 1122–28. http://dx.doi.org/10.1177/0954411920941383.
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A novel thin-walled direct-to-bone fixation ceramic cup was tested under critical impact loads simulating lateral fall and car crash scenarios. Three sizes of BIOLOX delta ceramic cups (total hip replacement cup with bearing diameter of 32 mm and two hip resurfacing cups with bearing diameters of 40 and 64mm) were implanted into reamed Sawbones blocks representing acetabulae. Three cups of each size were fully supported by the block and three were implanted with 15° of the cup’s outer diameter unsupported by the block. All testing was conducted with the corresponding bearing diameter heads lateralised by approximately 1 mm to represent worst case subluxed hips and all then subjected to test, replicating a lateral fall impact followed by a car crash impact. All cups passed lateral fall conditions without visible damage, although some movement of the cups was measured and damage to the blocks was observed. Five out of six of each cup size survived the car crash impacts with one fracture per size. In all cases, this was in the fully supported condition representing the highest cup inclination angle. The car crash impact force was equivalent to that reported to fracture the acetabulum and in all simulated cases, the Sawbones block showed signs of damage. Survival of five cups per size suggests the pelvis is much more likely to fracture before the cup. The ability of the cups to withstand these critical impact forces indicates they are unlikely to fracture in normal clinical use and should meet the more challenging demands of active patients likely to receive this device.
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Abdo, Jamil, E. Hassan, A. Al-Shabibi, and J. Kwak. "Design of a Testing Facility for Investigation of Drill Pipes Fatigue Failure." Journal of Engineering Research [TJER] 14, no. 2 (June 30, 2017): 105. http://dx.doi.org/10.24200/tjer.vol14iss2pp105-114.
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Drillstring and down-hole tool failure usually results from failing to control one or more of the vibration mechanisms. The solution starts with the ability to measure different modes of vibration, hence identifying different vibration mechanisms. Lateral, torsion and axial are vibration modes that take place when drill pipes run into problems downhole. Due to the three modes of vibration mechanisms such as bit bounce, stick-slip, lateral shocks, bit and bottom hole assembly (BHA) whirl, parametric and torsional resonance occur. Understanding the causes of the destructive loads is the main step towards developing approaches to prevent or reduce their effects, hence improving drilling performance. Vibration modes and mechanisms lead to failure of the drill pipes, BHA and drill bits. Drill pipes fatigue failure is very common due to capability of producing all vibration modes and mechanisms. Drill pipe and downhole tool assembly failure usually result from failing to have power over one or more of these vibration mechanisms. A novel in house experimental setup has been developed to mimic downhole axial, lateral and torsional vibration modes and mechanisms in drilling operations. In this paper, we focus on the design and construction of the testing facility. A number of tests were conducted to validate the capability and performance of the test setup. Drill pipe fatigue failure due to lateral cyclic stresses induced in the drill pipe has also been investigated and presented in this paper. The results show that operating on a rotation speed higher than 90% of the drillstring critical speed leads to yielding in the drillstring.
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Nur, M. R., H. Parung, and A. A. Amiruddin. "Analysis on the value of stiffness of the dual joint straightness notch joint of beams due to cyclic lateral load." IOP Conference Series: Earth and Environmental Science 921, no. 1 (November 1, 2021): 012019. http://dx.doi.org/10.1088/1755-1315/921/1/012019.
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Abstract Precast concrete is an answer to the demands of building structures that save time, but cannot be used widely because of the reliability of the connection, especially during an earthquake, the desired earthquake-resistant building structure must have sufficient strength and rigidity. Stiffness is one of the factors that determine the response of a structure to earthquake loads. When connected with earthquake loads, a structure must have sufficient rigidity so that its movement during an earthquake can be limited. This study aims to determine and analyze the stiffness in the double columns straight joint beam notches due to lateral cyclic load. By dividing 3 (three) types of test specimens, namely Monolithic column Beam, Type 1 Column Joint (SBK), and Type 2 Column Beam Joint (SBK). The connection used is a double straight notch and using the grouting method. Testing and analysis using the Displacement Control Method with the European Convention for Constructional Steelwork (ECCS) 1986 standards. The results showed the monolith column Column (BK) specimens have a greater stiffness value compared to SBK 1 specimens and SBK 2 specimens.
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Graham, R. Scott, Eric K. Oberlander, John E. Stewart, and David J. Griffiths. "Validation and use of a finite element model of C-2 for determination of stress and fracture patterns of anterior odontoid loads." Journal of Neurosurgery: Spine 93, no. 1 (July 2000): 117–25. http://dx.doi.org/10.3171/spi.2000.93.1.0117.
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Object. The finite element (FE) method is a powerful tool for the analysis of stress patterns of anatomical structures. In this study a highly refined FE model of C-2 was created and validated. The model was then used to characterize stress patterns, predicted fracture patterns, and transitions between Type II and Type III odontoid fractures. Methods. An anatomically accurate three-dimensional model of C-2 was created from computerized tomography data obtained from the Visible Human Project. The C-2 model was broken down into an FE mesh consisting of 32,815 elements and 40,969 nodes. For validation, the FE model was constrained and loaded to simulate that used in previous biomechanical studies. The validated model was then loaded in an iterative fashion, varying the orientation of the load within the validated range. A matrix of stress plots was created for comparative analysis. Results of the validation testing closely correlated with those obtained in previous biomechanical testing. Pure extension loading produced a Type III stress pattern with maximum stress of 134 MPa. Loading at 45° produced a Type II stress distribution with a maximum stress of 123 MPa. These stresses are within 3% and 11%, respectively, of the reported yield stress of cortical bone (138 MPa). In the second portion of the study, systematic variation in the orientation of the load vector revealed that higher stresses were associated with increased lateral angulation and increasing upward inclination of the load vectors. A transition from a Type III to Type II pattern occurred with lateral orientations greater than 15° and with compressive loads of 45°. Conclusions. The validated C-2 FE model described in this study both qualitatively and quantitatively was able to simulate the behavior of the C-2 vertebra in biomechanical testing. In this study the authors demonstrate the utility of the FE method when used in conjunction with traditional biomechanical testing.
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Nguyen, Thi Tuyet Trinh, Van Bac Nguyen, and Minh Quan Thai. "Flexural Strength of Partially Concrete-Filled Steel Tubes Subjected to Lateral Loads by Experimental Testing and Finite Element Modelling." Buildings 13, no. 1 (January 12, 2023): 216. http://dx.doi.org/10.3390/buildings13010216.
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In this paper, the flexural strength and buckling of the partially concrete-filled steel tubes (PCFST) under laterally repeated loads was investigated through three-point bending test configuration. Three-dimensional Finite Element (FE) models of the bending tests of the PCFST were developed, in which the concrete filling was modelled using elastic-plastic-fracture model capturing crack development and the tube steel was modelled using elastic-plasticity model. The bond between concrete and tube was considered as frictional touching contact. The validation showed the FE results including the ultimate flexural load and buckling failure mode of the steel tube were in excellent agreement with the experimental ones. A parametric study was then conducted using the verified FE models to investigate the effects of the tube diameter-to-thickness ratio, the concrete filling length ratio, the compressive strength of concrete, and the tube steel’s yield and tensile strengths on the PCFST’s ultimate flexural strength. Based on this study, buckling modes, the optimal concrete filling lengths, and the confined compressive strengths of concrete were determined considering the effects of all these parameters. The confined compressive stresses and strains in concrete predicted by the FE models were evaluated against those determined by theoretical models. The results revealed that the effects of concrete compressive strength to the PCFST’s flexural capacity was insignificant while increasing the tube diameter-to-thickness ratio or the tube steel’s yield and tensile strengths could significantly increase the PCFST’s flexural capacity and the confined compressive strength of concrete; and there was an optimal length of concrete filling at about 66% of the tube length. It demonstrated that the Finite Element analysis can therefore be used as a powerful method to the analysis and design the PCFST columns under lateral loads.
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Doubrovsky, M. P., I. Yu Dobrov, A. V. Gerashchenko, and O. M. Dubrovska. "MODEL TESTING OF PILED CLUSTERS AND LARGE MONO-PILES OF IMPROVED DESIGN." ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 2, no. 49 (October 17, 2017): 38–44. http://dx.doi.org/10.26906/znp.2017.49.822.
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When constructing piled clusters and structures supported by large mono-piles, piles designed are used to take up significant lateral and pressing-in loads. New effective and less resource-demanding design of piled cluster was considered before. At this paper some results of its model testing in laboratory conditions are analyzed and discussed. To increase energy-absorbing capacity of mooring/fender dolphins it was worked out and researched a new design of combined tubular mono-pile structure, incorporating internal flexible pile and damping element placed at the zone of pile head. This design has been tested by laboratory experiments using small scale model. Obtained results confirm its effectiveness and practicability.
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Giberti, Irene, Elisabetta Costa, Alexander Domnich, Valentina Ricucci, Vanessa De Pace, Giada Garzillo, Giulia Guarona, and Giancarlo Icardi. "High Diagnostic Accuracy of a Novel Lateral Flow Assay for the Point-of-Care Detection of SARS-CoV-2." Biomedicines 10, no. 7 (June 30, 2022): 1558. http://dx.doi.org/10.3390/biomedicines10071558.
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Highly accurate lateral flow immunochromatographic tests (LFTs) are an important public health tool to tackle the ongoing COVID-19 pandemic. The aim of this study was to assess the comparative diagnostic performance of the novel ND COVID-19 LFT under real-world conditions. A total of 400 nasopharyngeal swab specimens with a wide range of viral loads were tested in both reverse-transcription polymerase chain reaction and ND LFT. The overall sensitivity and specificity were 85% (95% CI: 76.7–90.7%) and 100% (95% CI: 98.7–100%), respectively. There was a clear association between the false-negative rate and sample viral load: the sensitivity parameters for specimens with cycle threshold values of <25 (>3.95 × 106 copies/mL) and ≥30 (≤1.29 × 105 copies/mL) were 100% and 50%, respectively. The performance was maximized in testing samples with viral loads ≥1.29 × 105 copies/mL. These findings suggest that the ND LFT is sufficiently accurate and useful for mass population screening programs, especially in high-prevalence and resource-constrained settings or during periods when the epidemic curve is rising. Other public health implications were also discussed.
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Wijewickreme, Dharma, Hamid Karimian, and Douglas Honegger. "Response of buried steel pipelines subjected to relative axial soil movement." Canadian Geotechnical Journal 46, no. 7 (July 2009): 735–52. http://dx.doi.org/10.1139/t09-019.
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The performance of buried steel pipelines subjected to relative soil movements in the axial direction was investigated using full-scale pullout testing in a soil chamber. Measured axial soil loads from pullout testing of pipes buried in loose dry sand were comparable to those predicted using guidelines commonly used in practice. The peak values of axial pullout resistance observed on pipes buried in dense dry sand were several-fold (in excess of 2 times) higher than the predictions from guidelines; the observed high axial pullout resistance is primarily due to a significant increase in normal soil stresses on the pipelines, resulting from constrained dilation of dense sand during interface shear deformations. This reasoning was confirmed by direct measurement of soil stresses on pipes during full-scale testing and numerical modeling. The research findings herein suggest that the use of the coefficient of lateral earth pressure at-rest (K0) to compute axial soil loads, employing equations recommended in common guidelines, should be undertaken with caution for pipes buried in soils that are likely to experience significant shear-induced dilation.
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Spang, Robert, Jonathan Egan, Philip Hanna, Aron Lechtig, Daniel Haber, Joseph P. DeAngelis, Ara Nazarian, and Arun J. Ramappa. "Comparison of Patellofemoral Kinematics and Stability After Medial Patellofemoral Ligament and Medial Quadriceps Tendon–Femoral Ligament Reconstruction." American Journal of Sports Medicine 48, no. 9 (June 18, 2020): 2252–59. http://dx.doi.org/10.1177/0363546520930703.
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Background: There is a lack of evidence regarding the optimum extensor-sided fixation method for medial patellofemoral ligament (MPFL) reconstruction. There is increased interest in avoiding patellar drilling via soft tissue–only fixation to the distal quadriceps, thus reconstructing the medial quadriceps tendon–femoral ligament (MQTFL). The biomechanical implications of differing extensor-sided fixation constructs remain unknown. Hypothesis: The null hypothesis was there would be no differences between traditional MPFL reconstruction and MQTFL reconstruction with respect to resistance to lateral translation, patellar position, or patellofemoral contact pressures. Study Design: Controlled laboratory study. Methods: Nine adult knee specimens were mounted on a jig that applied static, physiologic loads to the quadriceps tendons. Patellar position and orientation, knee flexion angle, and patellofemoral pressure were recorded at 8 different flexion angles between 0° and 110°. Additionally, a lateral patellar excursion test was conducted wherein a load was applied directly to the patella in the lateral direction with the knee at 30° of flexion and subjected to 2-N quadriceps loads. Testing was conducted under 4 conditions: intact, transected MPFL, MQTFL reconstruction, and MPFL reconstruction. For MQTFL reconstruction, the surgical technique established by Fulkerson was employed. For MPFL reconstruction, a traditional technique was utilized. Results: The patellar excursion test showed no significant difference between the MQTFL and intact states with respect to lateral translation. MPFL reconstruction led to significantly less lateral translation ( P < .05) than all other states. There were no significant differences between MPFL and MQTFL reconstructions with respect to peak patellofemoral contact pressure. MPFL and MQTFL reconstructions both resulted in increased internal rotation of the patella with the knee in full extension. Conclusion: Soft tissue-only extensor-sided fixation to the distal quadriceps (MQTFL) during patella stabilization appears to re-create native stability in this time 0 cadaver model. Fixation to the patella (MPFL) was associated with increased resistance to lateral translation. Clinical Relevance: Evolving anatomic knowledge and concern for patellar fracture has led to increased interest in MQTFL reconstruction. Both MQTFL and MPFL reconstructions restored patellofemoral stability to lateral translation without increasing contact pressures under appropriate graft tensioning, with MQTFL more closely restoring native resistance to lateral translation at the time of surgery.
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Fujii, Tatsuya, Makoto Tateura, Masato Ogawa, and Satoru Ozeki. "Ultimate Load Measuring System for Fixation of Soft Tissue to Bone." Foot & Ankle International 43, no. 2 (September 30, 2021): 253–59. http://dx.doi.org/10.1177/10711007211040504.
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Background: The initial ultimate load for graft fixation is one of the essential factors in the reconstruction of lateral ankle ligaments. Several anchoring devices have been developed to fix the substitute ligament into the bone. A fair comparison of these fixation methods warrant a reproducible examination system. The purpose of this study was to make an experimental animal model and to compare the initial ultimate loads of 3 graft fixation methods, including the use of EndoButton (EB), interference screw (IFS), and a novel socket anchoring (SA) technique. Methods: Porcine calcaneus bones and 5-mm-wide split bovine Achilles tendons were used as fixation bases and graft materials, respectively. Both ends were firmly sutured side-by-side, using the circumferential ligation technique as a double-strand substitute that was 45 mm in length. Porcine calcanei with similar characteristics to adult human calcanei were mounted on a tensile testing machine, and substitutes were fixed into bones using the 3 fixation methods. A polyester tape was passed through the tendon loop and connected to a crosshead jig of the testing machine. The initial ultimate loads were measured in 15 specimens for each fixation method to simulate a lateral ankle ligament (LAL) injury. Results: The ultimate loads (ULs) were 223.6 ± 52.7 N for EB, 229.7 ± 39.7 N for SA, and 208.8 ± 65.3 N for IFS. No statistically significant difference was observed among the 3 groups ( P = .571). All failures occurred at the bone–ligament substitute interface. Conclusion: The initial ULs in all 3 fixation methods were sufficient for clinical usage. These values were larger than the UL of the anterior talofibular ligament; however, these were smaller than the UL of the calcaneofibular ligament. Clinical Relevance: In an experimental animal model, ULs for SA, EB, and IFS techniques showed no significant difference. All failures were observed in the fixation site of the calcaneus and were overwhelmingly related to suture fixation failure.
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Zhang, Xihong, Hong Hao, and Chao Li. "The effect of concrete shear key on the performance of segmental columns subjected to impact loading." Advances in Structural Engineering 20, no. 3 (July 28, 2016): 352–73. http://dx.doi.org/10.1177/1369433216650210.
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Conventional precast segmental columns with seismic resistance design consist of only flat concrete segments with prestress tendon. This is because friction between adjacent segments is sufficient to resist the lateral forces from earthquake-induced actions. However, the friction between segments is not necessarily sufficient to resist lateral impact loads such as vehicle impact the column might experience during its service life. This article investigates the effectiveness of using concrete shear key in segments of precast segmental column in resisting the lateral impact loading. The precast reinforced concrete segments were designed with concrete shear keys to improve the column shear resistance capacity and minimize the relative displacement between adjacent segments. Two groups of segmental columns with and without shear key were designed and tested using a pendulum impact system. The effectiveness of shear key in resisting lateral impact loads was analysed by comparing the performance of the two groups of segmental columns. The testing results revealed that by introducing concrete shear key to segmental column, the relative displacement between adjacent segments could be effectively reduced. However, the large concrete shear key increased stress concentration in the concrete segments. Relatively, more severe damages to concrete segments were found on the columns with shear key. Further improvements on shear key designs should be made for better performance of segmental columns against impact loading.
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van Santen, J. W., and C. J. Coetzee. "Design of a Test Setup for Measuring all Load Components Acting on Tillage and Planting Implements." R&D Journal 38 (June 1, 2022): 1–14. http://dx.doi.org/10.17159/2309-8988/2022/v38a2.
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This project entailed the design, manufacture, and testing of a test setup with the ability to measure all load components acting on tillage and planting implements. In future, data obtained with the test setup can be used to perform accurate design calculations, as input into finite element simulations, and to perform accurate fatigue analysis. The design of implements can therefore be improved to better withstand the loads under various operational conditions and to minimise fatigue cracking. Laboratory controlled testing, and subsequent field tests, proved that the designed test setup was able to isolate and accurately measure each of the three orthogonal load components, as well as the main moment. It was further shown that the remaining two moments could be accurately calculated using the measured load components and fixed geometric lengths. The conclusion was drawn, based on field tests, that an increase in speed with the tine ripper had no significant effect on the mean load. Further, an increase in the working depth, resulted in an increase in the load, especially in the draught and vertical directions. Finally, it was shown that a decrease in turning radius (a tighter turn), resulted in an increase in the lateral force component.
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Qin, Li Kun, Yu Pu Song, Yu Jie Wang, De Shen Zhao, and Jia Wei Yao. "Mechanics Characteristics and Failure Criteria of Concrete Confined by One-Way Lateral Stress after Suffering High Temperature." Key Engineering Materials 324-325 (November 2006): 707–10. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.707.
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Biaxial compressive tests of plain concrete specimens under normal temperature and suffering high temperature(200600 )were completed under four lateral constant stress rates. The tests were completed by using the large static-dynamic triaxial test system for concrete in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology. The biaxial compressive strength and deformation characteristics of concrete confined by lateral stress after suffering different temperature were studied in a systematic way. On the basis of the tests, the failure criterion of concrete subjected to constant lateral compressive stress after suffering different temperature was established in the Octahedral stress space. The conclusions can provide the testing and theoretical basis for deeper study of the concrete construction subjected to biaxial compressive combined loads suffering different temperature such as chimney, building after fire and safety shell for nuclear reactor.
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Kitayama, Kazuhiro, and Hiromu Katae. "Earthquake resistance of reinforced concrete corner beam-column joints with different column axial loads under bi-directional lateral loading." Bulletin of the New Zealand Society for Earthquake Engineering 50, no. 4 (December 31, 2017): 527–36. http://dx.doi.org/10.5459/bnzsee.50.4.527-536.
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The seismic performance of a corner beam-column joint in reinforced concrete frames was studied by testing two three-dimensional corner beam-column subassemblage specimens without slabs under constant column axial load and bi-directional lateral cyclic load reversals. The column-to-beam flexural strength ratio was varied from 1.4 to 2.3 by changing the magnitude of column axial load. Although a sufficient margin to prevent shear failure was provided to a corner beam-column joint in the test, the subassemblage specimens failed in joint hinging after beam and column longitudinal bars and joint hoops yielded. The ultimate joint hinging capacity of a corner joint under bi-directional lateral loading was enhanced by an increase in column compressive axial load, and can be estimated based on the new mechanism proposed by Kusuhara and Shiohara.
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Wang, Teng, and Wenlong Liu. "Development of cyclic p–y curves for laterally loaded pile based on T-bar penetration tests in clay." Canadian Geotechnical Journal 53, no. 10 (October 2016): 1731–41. http://dx.doi.org/10.1139/cgj-2015-0358.
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Offshore pile foundations are always subjected to cyclic lateral loads, which can result in the remolding and softening of the surrounding seabed soil. Cyclic T-bar penetrometer testing provides a rapid and effective method for assessing the remolded shear strength. It is widely believed that the soil strength degrades with the accumulation of plastic strain, but the strain cannot be measured. Numerical analysis described in this paper shows that the accumulated plastic displacement of the T-bar in a cyclic range of two diameters is approximately equal to its accumulated displacement. By using T-bar test data, a cyclic degradation model based on the accumulated (plastic) displacement is developed to describe the soil strength degradation at a given depth. Furthermore, an improved p–y curve model based on the cyclic degradation model is proposed to estimate the lateral response of pile under cyclic loads. The improved p–y curve model was embedded into the OpenSees program to investigate the cyclic lateral responses of soil elements and the pile. A case study was conducted to verify the improved p–y curve model by comparing it with published centrifuge experiment data. Results indicate that the improved p–y curve model based on T-bar test data is highly precise and practicable.
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Arrigoni, Paolo, Davide Cucchi, Francesco Luceri, Alessandra Menon, Carlo Zaolino, Andrea Zagarella, Michele Catapano, et al. "Lateral Elbow Laxity Is Affected by the Integrity of the Radial Band of the Lateral Collateral Ligament Complex: A Cadaveric Model With Sequential Releases and Varus Stress Simulating Everyday Activities." American Journal of Sports Medicine 49, no. 9 (June 11, 2021): 2332–40. http://dx.doi.org/10.1177/03635465211018208.
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Background: An elongation of the radial lateral collateral complex (R-LCL) can provoke symptomatic minor instability of the lateral elbow leading to lateral elbow pain. Biomechanical models investigating the effects of elongation and partial or complete lesions of the R-LCL on lateral elbow stability are lacking. Purpose: To evaluate how partial and complete R-LCL release affects radiocapitellar joint stability in a setting of controlled varus load and progressive soft tissue release. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen cadaveric specimens were obtained and mounted on a custom-made support to control elbow flexion and extension and to allow for controlled varus loading. Stress tests were performed on all intact specimens under gravity load alone, a 0.5-kg load applied to the hand, and a 1-kg load applied to the hand. After load application, anteroposterior radiographs were obtained. The following release sequence was applied to all specimens: release of the anterior half of the common extensor origin, pie crusting of the R-LCL, and R-LCL release. After each release, stress tests and radiographs were performed. The varus joint angulation of the elbow (α) was measured by 2 examiners as the main outcome parameter. Results: Significant changes in α from the initial condition occurred after each release, and a significant effect of varus load on α was documented for all release steps. A significant effect of the releases on α could be documented for all identical varus load conditions. A linear regression model was generated to describe the effect of varus load on α. Conclusion: Varus loads simulating everyday activities produce changes in the varus joint angulation of the elbow already in the intact specimen, which are linearly dependent on the applied moment and persist after release of the lateral stabilizing structures. With progressive load, a pie crusting of the R-LCL is the minimal procedure able to provoke a significant change in the varus joint angulation, and a complete R-LCL release produces additional increase in the varus joint angulation in all testing conditions. Clinical Relevance: These findings confirm the role of the R-LCL as static lateral stabilizer, supporting a pathological model based on its insufficiency and culminating with a symptomatic minor instability of the lateral elbow.
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Jafari, M., M. S. Sakib, D. T. Griffith, I. Brownstein, B. Strom, and J. Cooney. "Wind Tunnel Experiment to Study Aerodynamics and Control of H-Rotor Vertical Axis Wind Turbine." Journal of Physics: Conference Series 2265, no. 2 (May 1, 2022): 022084. http://dx.doi.org/10.1088/1742-6596/2265/2/022084.
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Abstract This study focuses on wind tunnel testing of a 3-bladed H-rotor vertical axis wind turbine (VAWT) under various conditions. Different performance metrics such as power coefficient (CP ), thrust load coefficient (CX ), and lateral load coefficient (CY ) are presented at four wind speeds. Parked loads, which are key parameters in designing VAWTs, are reported for the baseline case. Apart from presenting the benchmark results for the baseline model, the impact of two control strategies to boost the energy production of the VAWT are investigated. First, the effect of installing the plasma actuators on all blades is tested at four plasma input voltages. The results indicate that plasma actuators are an efficient approach to enhance the aerodynamic efficiency of VAWTs through modification of drag and lift loads acting on the blades. The second control strategy evaluated is intracycle RPM control. In this control method, the rotational speed of the turbine is varied with the azimuthal location of blades at each cycle so that the power production is increased. The results observed for this control strategy encourage further research development to expand the limited knowledge on its application for VAWTs.