Academic literature on the topic 'Two-point loading'
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Journal articles on the topic "Two-point loading"
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Sangeetha, Palanivelu, S. Ramana Gopal, A. Jai Vigneshwar, K. Vaishnavi, and A. Srinidhi. "Flexural Strength of Steel-Concrete Composite Beams Under Two-Point Loading." Civil and Environmental Engineering Reports 30, no. 4 (December 1, 2020): 21–32. http://dx.doi.org/10.2478/ceer-2020-0047.
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Abstract This study investigates the flexural strength of simply-supported steel–concrete composite beams under two-point loading. A total of four specimens were tested to failure for varying parameters including type of connectors (stud and channel) and number of connectors (two and four). ANSYS software was used to establish the finite element models that can simulate the flexural behaviour of the composite beam. The test results show that a beam with channel connectors performs better than a beam with stud connectors. The composite beam with two connectors between the beam and slab causes additional deflection due to slippage in the connectors, when compared to the beam with four connectors. The results from the analytical model are in good agreement with the experimental results.
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Langley, R. S. "THE RESPONSE OF TWO-DIMENSIONAL PERIODIC STRUCTURES TO IMPULSIVE POINT LOADING." Journal of Sound and Vibration 201, no. 2 (March 1997): 235–53. http://dx.doi.org/10.1006/jsvi.1996.0744.
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Hanson, M. T. "Elastic Fields Resulting From Concentrated Loading on a Three-Dimensional Incompressible Wedge." Journal of Applied Mechanics 62, no. 3 (September 1, 1995): 557–65. http://dx.doi.org/10.1115/1.2895981.
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This paper considers point force or point moment loading applied to the surface of a three-dimensional wedge. The wedge is two-dimensional in geometry but the loading may vary in a direction parallel to the wedge apex, thus creating a three-dimensional problem within the realm of linear elasticity. The wedge is homogeneous, isotropic, and the assumption of incompressibility is taken in order for solutions to be obtained. The loading cases considered presently are as follows: point normal loading on the wedge face, point moment loading on the wedge face, and an arbitrarily directed force or moment applied at a point on the apex of the wedge. The solutions given here are closed-form expressions. For point force or point moment loading on the wedge face, the elastic field is given in terms of a single integral containing associated Legendre functions. When the point force or moment is at the wedge tip, closed-form (nonintegral) expressions are obtained in terms of elementary functions. An interesting result of the present research indicates that the wedge paradox in two-dimensional elasticity also exists in the three-dimensional case for a concentrated moment at the wedge apex applied in one direction, but that it does not exist for a moment applied in the other two directions.
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Quadri, Ajibola Ibrahim. "Strut and Tie Modelling of Reinforced Concrete Deep Beams Under Static and Fixed Pulsating Loading." Al-Nahrain Journal for Engineering Sciences 23, no. 3 (November 24, 2020): 306–12. http://dx.doi.org/10.29194/njes.23030306.
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Numerical analysis of the performance of reinforced concrete (RC) deep beam subjected to static and fixed-point pulsating loading at the midpoint has been investigated. Three-dimensional nonlinear finite element model using the Strut and Tie approach was adopted. The damage level under the influence of the applied fixed pulsating loading is higher than the static applied loading, hence early crack was observed because of the stepwise loading in the form of vibration. Although the Strut and Tie approach gave a good estimation of the resistance capacity of the beam, the beam undergo high shear damage when subjected to these two types of loading. Material strength properties, applied loadings and cross-sections adopted are some of the factors that affect the performance of the deep beam.
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Wu, X. F., Y. A. Dzenis, and W. S. Zou. "Interfacial edge crack between two bonded dissimilar orthotropic strips under antiplane point loading." ZAMM 83, no. 6 (June 20, 2003): 419–22. http://dx.doi.org/10.1002/zamm.200310063.
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Kochergin, Victor, Igor Maksimov, Victor Pevzner, and Evgeniya Polunina. "Track loading on Russian Railways under modern maintenance conditions." E3S Web of Conferences 135 (2019): 02002. http://dx.doi.org/10.1051/e3sconf/201913502002.
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Rail fasteners loading and its influence on the track deformability under modern maintenance conditions with increased cars axle loads is observed. The difference between oneand two-point wheelrail contact loading scheme is shown. The authors present the analysis of domestic and foreign methods of pads bench tests and show the necessity of carrying out tests imitating real (two-point contact) loading of pads. The bench test method for researching fastener loading and pad strain characteristics in a wide range of vertical and lateral loads under two-point contact scheme based on a number of field tests is presented. The results of static tests and following dynamic ones with cycling loading, which were carried out on a two-sleepers bench, are observed. Bench tests carried out by VNIIZHT and the analysis of the cyclic test methods showed the importance of fasteners tests with a real loading simulation making it possible to explain the causes of track gauge widening and decrease of track inclination, which considerably influences track stability and wear of the track and rolling stock.
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Meynendonckx, J., G. Heuvelmans, B. Muys, and J. Feyen. "Effects of watershed and riparian zone characteristics on nutrient concentrations in the River Scheldt Basin." Hydrology and Earth System Sciences Discussions 3, no. 3 (May 2, 2006): 653–79. http://dx.doi.org/10.5194/hessd-3-653-2006.
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Abstract. The relative influence of a set of watershed characteristics on surface water nutrient concentrations was examined in 173 watersheds within two subcatchments (Upper-Scheldt and Nete) of the River Scheldt Basin (Flanders, Belgium). Each watershed was described by seasonal rainfall, discharge loading of point sources, morphological characteristics (area, average slope, drainage density, elongation), land use and soil properties (soil texture and drainage). Partial regression analysis revealed that soil drainage variables had the strongest influence on nutrient concentrations. Additional influence was exerted by land use and point source loading variables. Nitrate concentrations were positively correlated with effluent loadings coming from wastewater treatment plants and with the area of agricultural land. Phosphate concentrations were best explained by effluent loadings of industrial point sources and by the area of urban land. Land use close to the river was not a better predictor of nitrate and phosphate concentrations than land use away from the river. This suggests that the mediating impact of riparian zones is rather explained by the hydrologic pathways within the buffer strip.
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Meynendonckx, J., G. Heuvelmans, B. Muys, and J. Feyen. "Effects of watershed and riparian zone characteristics on nutrient concentrations in the River Scheldt Basin." Hydrology and Earth System Sciences 10, no. 6 (November 28, 2006): 913–22. http://dx.doi.org/10.5194/hess-10-913-2006.
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Abstract. The relative influence of a set of watershed characteristics on surface water nutrient concentrations was examined in 173 watersheds within two subcatchments (Upper-Scheldt and Nete) of the River Scheldt Basin (Flanders, Belgium). Each watershed was described by seasonal rainfall, discharge loading of point sources, morphological characteristics (area, average slope, drainage density, elongation), land use and soil properties (soil texture and drainage). Partial regression analysis revealed that soil drainage variables had the strongest influence on nutrient concentrations. Additional influence was exerted by land use and point source loading variables. Nitrate concentrations were positively correlated with effluent loadings coming from wastewater treatment plants and with the area of agricultural land. Phosphate concentrations were best explained by effluent loadings of industrial point sources and by the area of urban land. Land use close to the river was not a better predictor of nitrate and phosphate concentrations than land use away from the river. This suggests that the mediating impact of riparian zones is rather explained by the hydrologic pathways within the buffer strip.
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Morshed, M. M. Maruf, Anthony C. Zander, and Colin H. Hansen. "Two-Dimensional and Three-Dimensional Acoustic Loading on Cylinders Due to a Point source." AIAA Journal 49, no. 11 (November 2011): 2421–29. http://dx.doi.org/10.2514/1.j050749.
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He, Ran, Xing Ping Shu, and Bo Wang Chen. "Test on Eccentricaly Loaded Four-Tube Concrete-Filled Steel Tubular (CFST) Laced Columns of No Yield Point." Applied Mechanics and Materials 204-208 (October 2012): 4658–63. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.4658.
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In order to study the characteristics about deformation and stress of four-tube concrete-filled steel tubular(CFST) laced columns of no yield point, a test with the parameter of eccentricity on two our-tube concrete-filled steel tubular(CFST) laced columns of no yield point has been finished by means of 500t press. The results of the test shows that the larger the eccentricity, the more obvious the global deformation of laced columns tends to become, and the four-tube CFST laced columns of no yield point under eccentric compression were subjected to overall bending failure and ductile failure with obvious premonition; In the meanwhile, confinement effect of main tubes away from the loading point of laced columns under eccentric compression was inapparent , while confinement effect of the two main tubes close to the loading point begain to play and increase before it was to fail, which made the characteristics about deformation and stress of the the two main tubes close to the loading point similar to the single CFST column under axial compression.
Dissertations / Theses on the topic "Two-point loading"
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Ho, Ming-Shen, and 何明紳. "Numerical Modeling of Simple Supported Beam under Two－Point Loading." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/ubu3c4.
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碩士國立臺北科技大學
土木與防災研究所
101
Reinforced concrete design manual generally ignores the contribution from concrete tensile strength, this will underestimate the capacity of maximum bending moment of reinforced concrete structure. This study will develop a mechanical theory numerical analysis model, using the MATLAB mathematical software implemented with the constitutive relations of concrete and reinforcement bar to analyze the tensile and compressive strains of reinforcement bar of a simple supported beam under two-point load. The calculated strains are compared with the experimental results measured form SOFO fiber sensors attached to the reinforcement bars in a reinforced concrete beam. The calculated moments along the beam are identical to the theoretical solution, this indicate this numerical analysis model is functioning well. Furthermore, for the pure bending section, the calculated compressive strains are in good agreement with the measured strains. However the calculated tensile strains are somewhat offset from the measured values. In addition, FLAC3D, a finite difference software, is used to analyzed the same instrumented beam, in which Mohr Coulomb is used to model concrete and linear elasticity is used to model reinforcement bar. When applied load is smaller than 1150kg, the calculated strains from FLAC3D are in good agreement with the results from mechanical theory numerical analysis model as well as experimental results.
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Huang, Chien-Chang, and 黃健彰. "Transient Analysis of a Two-Layered Piezoelectric Medium Subjected to Dynamic Mechanical and Electrical Point Loading." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/93853444310427736217.
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碩士淡江大學
航空太空工程學系碩士班
100
In this study, transient elastic waves propagating in a two-layered piezoelectric medium subjected to dynamic mechanical and electrical point loading in the upper layer are investigated. This structure is a two-layered composite laminate constituted by two layers of different thickness of piezoelectric materials. The one-sided and the two-sided Laplace transforms is applied to obtain the shear stresses and the electric displacements in the Laplace transform domain. And then, the Durbin’s method for the one-sided Laplace transform inversion and the extended Durbin’s method for the two-sided Laplace transform inversion are used to carry out the numerical inversion. Finally, the numerical results for different field points, different ratios of thickness, and different loading types are evaluated and discussed in detail.
Books on the topic "Two-point loading"
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United States. National Highway Traffic Safety Administration and University of Michigan. Transportation Research Institute, eds. Study of differences in Hybrid III chest deflections due to three-and two-point belt loadings. Washington, D.C.]: U.S. Dept. of Transportation, National Highway Traffic Safety Administration, 1988.
Find full textBook chapters on the topic "Two-point loading"
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Ananth, M., R. Sivasankar, G. Selvaganapathy, and T. Sevakapandian. "Analysis of RCC Beam with Varying Stirrups Pattern Subjected to Two-Point Loading by Using ABAQUS." In Lecture Notes in Civil Engineering, 377–86. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-6403-8_32.
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Piotrowski, J. "On an Approach to Prediction of Contact Loading of Rail for Two-Point Contact Between Wheel and Rail." In Rail Quality and Maintenance for Modern Railway Operation, 215–24. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-015-8151-6_17.
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Chen, Zhexian, Wenfu He, Sen Yang, Cheng Chang, and Min Ji. "Seismic Performance of a Precast Hollow Insulated Shear Wall." In Lecture Notes in Civil Engineering, 430–39. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-1260-3_39.
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AbstractA new precast hollow insulation shear wall (PHISW) is proposed in this paper. To study the seismic behaviors of the new PHISW, two cast-in-place solid shear wall (CSW) specimens, two precast monolithic hollow insulated shear wall (PMW) specimens, and two precast hollow insulated shear wall (PSW) specimens with vertical seams were produced and subjected to low-cyclic reversed loadings. The seismic indices obtained from low-cyclic reversed tests include the failure pattern, hysteretic curves and energy dissipation. The experiment results indicate that flexural failure is the main failure mode of the specimens, but a noticeable difference is detected in the cracking distribution between the three types of shear walls. The bearing capacity of each characteristic point of PMW and PSW is comparable to that of CSW. The ductility coefficient of the newly proposed precast shear wall is slightly lower than that of CSW.
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Mukherjee, Suvabrata, and Provas Kumar Roy. "Application of Moth-Flame Optimization Algorithm for the Determination of Maximum Loading Limit of Power System." In Advances in Environmental Engineering and Green Technologies, 78–93. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-5225-8551-0.ch003.
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Moth-flame optimization algorithm (MFOA) based on the navigation strategy of moths in universe is a novel bio-inspired optimization technique and has been exerted for determining the maximum loading limit of power system. This process is highly effective for traversing long distances following a straight path. As a matter of fact, moths follow a deadly spiral path as artificial lights tend to confuse them. Exploration and exploitation are two vital aspects of the algorithm, used in tuning of the parameters. The algorithm is verified on MATPOWER case30 and case118 systems. Comparison of the performance of MFOA has been done with other evolutionary algorithms such as multi-agent hybrid PSO (MAHPSO), differential evolution (DA), hybridized DE, and PSO (DEPSO). The performance of MFOA in determining maximum loading limit is verified from the results. In much reduced time, MFO algorithm also gives high maximum loading point (MLP).
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Roy, Provas Kumar, Moumita Pradhan, and Tandra Pal. "Evolutionary Algorithms for Economic Load Dispatch Having Multiple Types of Cost Functions." In Handbook of Research on Natural Computing for Optimization Problems, 201–26. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-5225-0058-2.ch009.
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This chapter presents various novel evolutionary algorithms, namely Real Coded Genetic Algorithm (RGA), two variants of Biogeography-Based Optimization (BBO), and three variants of Particle Swarm Optimization (PSO) in order to find the optimal power generation scheduling to simultaneously optimize fuel cost and power loss for solving constrained economic load dispatch problems of all thermal systems, considering multiple fuel operation and valve point effect. The effectiveness of the proposed algorithms is demonstrated in five different ELD problems, considering different constraints such as transmission losses, ramp rate limits, multi-fuel options and valve point loading. Comparative studies are carried out to examine the effectiveness and superiority of the proposed approaches. A comparison of simulation results reveals optimization usefulness of the proposed BBO scheme over other well established population based optimization techniques. It is also found that the convergence characteristics of the BBO algorithm are better than other optimization methods.
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Karakus, Murat, Ashton Ingerson, William Thurlow, Michael Genockey, and Jesse Jones. "A New Acoustic Energy-Based Method to Estimate Pre-Loads on Cored Rocks." In Advances in Civil and Industrial Engineering, 281–325. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-2709-1.ch008.
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The Acoustic Emission (AE) due to the sudden release of energy from the micro-fracturing within the rock under loading has been used to estimate pre-load. Once the pre-load is exceeded an irreversible damage occurs at which AE signals significantly increase. This phenomenon known as Kaiser Effect (KE) can be recognised as an inflexion point in the cumulative AE hits versus stress curve. In order to determine the value of pre-load (sm) accurately, the curve may be approximated by two straight lines. The intersection point projected onto the stress axis indicates the pre-load. However, in some cases locating the point of inflexion is not easy. To overcome this problem we have developed a new method, The University of Adelaide Method (UoA), which use cumulative acoustic energy. Unlike existing methods, the UoA method emphasises the energy of each AE, the square term of the amplitude of each AE. As the axial pre-load is exceeded, the micro cracks become larger than the existing fractures and therefore energy released with new and larger cracks retain higher acoustic energy.
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Kubade, Pravin R., Amol N. Patil, and Hrushikesh B. Kulkarni. "Structure Properties Relationship Studies of Vinyl Ester Hybrid Syntactic Foam." In Handbook of Research on Advancements in Manufacturing, Materials, and Mechanical Engineering, 368–94. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4939-1.ch018.
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Syntactic foam is the porous composite produced by mixing prefabricated hollow spherical particle into the matrix. Syntactic foams are used as energy absorption sandwich core for several applications like marine, automotive, and aerospace. In this work, low density hollow glass microspheres are hybridized with fly ash cenosphere in Bisphenol-A epoxy-based vinyl ester matrix. Hybrid syntactic foams is created with 60% total filler content. Within these hybrid systems internal composition of two fillers were varied in a step of 25 vol% with respect to each other. Hybrid syntactic foams are prepared by the hand lay-up (molding) method. The physical characterization parameter contains density and matrix porosity whereas tensile, quasi-static compression, flexural (3-point bending), Izod impact, and micro Vickers hardness are grouped as mechanical characterization parameters. Scanning electron microscopy was performed on fractured surfaces to examine deformation and fracture mechanisms related with each loading condition.
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Weaver, J. "Gender Role Inventory." In Handbook of Research on Electronic Surveys and Measurements, 367–70. IGI Global, 2007. http://dx.doi.org/10.4018/978-1-59140-792-8.ch054.
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We describe a newly developed 14-item inventory designed to measure two dimensions – agency and communion – of gender role self perceptions. The Gender Role Inventory (GRI-14) emerges as a conceptual and empirical refinement of the Bem Sex Role Inventory (BSRI; Bem, 1981) offering exceptional utility for electronic-based research while overcoming questions about construct validity and psychometric adequacy inherent in the BSRI. Since its inception, the BSRI has proven a widely used tool for assessing femininity and masculinity in numerous empirical studies and, to a significant extent, has defined the nature of sex role orientation in the research literature. Despite its popularity, however, persistent questions have arisen over whether the BSRI actually measures what it claims to measure (see, for example, Choi & Fuqua, 2003; Hoffman & Borders, 2001). A highly consistent pattern emerging across a range of factor-analytic studies, for example, is (1) a single femininity factor and two or more complex masculinity factors, (2) a tendency toward inconsistent item loading across these factors (e.g., over half of the femininity subscale items do not load on the femininity factor), and (3) an unexpectedly low amount of total variance typically accounted for by the primary factors. Concerns such as these, some argue, point to an “initial lack of theoretically defined dimensions of masculinity/femininity measured by the BSRI” (Choi & Fuqua, 2003, p. 884) while others proposed that the BSRI actually measures constructs such as instrumentality and expressiveness (e.g., Bohannon & Mills, 1979; Moreland, 1978).
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R. Rusnak, Cameron, and Craig C. Menzemer. "Fatigue Behavior of Reinforced Welded Hand-Holes in Aluminum Light Poles with a Change in Detail Geometry." In Structural Health Monitoring of Structure and Infrastructure Systems – History, Applications, Challenges, and Future [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106342.
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Welded aluminum light poles often contain hand-holes. These hand-holes are used to give access for electrical wiring installation and maintenance purposes. Wind load may cause light poles to be loaded in a cyclic manner. This cyclic loading can cause localized fatigue cracking around the hand-hole. Fatigue failure around hand-holes has been observed in the field, but studies surrounding the resistance of the hand-holes are few and far between. This study included four-point bending fatigue tests on welded aluminum poles containing hand-holes. Eight welded aluminum specimens, each with two hand-holes, were tested in fatigue. These 16 details were loaded at the same stress range. Each specimen had a slightly different geometry or treatment applied to the hand hole. These different details mimicked traditional reinforced hand holes, similar to those evaluated in previous studies. Changes in the treatment and/or geometry included milling the inside of hole, milling the inside of the hole as well as the cast insert prior to welding, and milling the cast insert itself prior to welding. Among the 16 details tested, 15 failed as a result of fatigue cracking. It was found that specimen failure would originated in the throat of the fillet weld and then proceeded to propagate into the reinforcement ring/casting. A finite element analysis was used in addition to the experimental study.
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Pasha, S. "How different the scoliotic curves are?" In Studies in Health Technology and Informatics. IOS Press, 2021. http://dx.doi.org/10.3233/shti210434.
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The pathomechanism of spinal deformity development in adolescent idiopathic scoliosis (AIS) has been related to the sagittal curvature of the spine. It is not known how the variations in the sagittal profile relates to the coronal deformity patterns in AIS. A total of 70 Lenke 1 and 50 Lenke 5 AIS patients were included retrospectively. A finite element (FE) model was developed for each spine where the sagittal spinal curvatures were modeled as 2D S shaped elastic rods. Transverse plane deformation patterns of these rods under physiological loading were determined and clustered based on their similarities. The patients’ characteristics, including the Lenke type, and the spinal measurements in these deformation pattern clusters were statistically compared. Three different axial deformation patterns were determined from the FE simulations of the 120 sagittal curves. Two axial groups were looped shaped in opposing directions (Group I and III) and one was lemniscate shaped (Group II). 94% of the patients in Groups I and II were Lenke 1 and 100% of Group III was Lenke 5. The position of the sagittal inflection point moved downward from Group I-III resulting in significantly different ratio of the arc lengths above and below the sagittal inflection points for Groups I, II and III (0.49±0.59, 1.15±0.44, and 3.22±1.8). A classification of idiopathic scoliosis, based on the biomechanics of S-shaped flexible rods deformation could distinguish between different coronal curve types. The geometrical parameters of the sagittal profiles in the axial deformation pattern groups were significantly different.
Conference papers on the topic "Two-point loading"
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Ngabonziza, Yves, Claudia Boldrini, Benjamin Liaw, Jackie Li, and Feridun Delale. "Damage Self-Diagnosis in Carbon Fiber-Reinforced Composites Under Fatigue Loading." In ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2010. http://dx.doi.org/10.1115/smasis2010-3870.
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An experimental study was conducted to sense interlaminar delamination in carbon-fiber composites utilizing inherent material piezoresistivity. Damage detection was carried out using discrete electrodes mounted on a Double Cantilever Beam (DCB) specimen. The DCB composite specimens were tested for fatigue interlaminar fracture. The traditional two-point probe and four-point probe technique were employed to measure the through-thickness electrical resistance change. Optical marker method was also used to detect interlaminar crack growth. The results show that the two-point probe measurements did not capture effectively the delamination propagation while the four-point probe measurement showed a promising sensing capability in terms of delamination propagation.
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Ekwaro-Osire, S., M. P. H. Khandaker, and K. Gautam. "Probabilistic Analysis of Notched Micro Specimen Under Three-Point Loading." In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-85493.
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Stress singularity arises in MEMS devices due to sudden geometric and material variation. Sharp notches are common example of sudden geometric variation, which often occurs during the fabrication process of MEMS components. The magnitude of the stress field induced due to stress singularity is given by the value of the notch stress intensity, K. The stress intensity is depended on the notch geometry and the type of loading (mode I, mode II and mode III). Fracture failure at the notch occurs when notch stress intensity reach fracture toughness, KC. An electrostatically actuated test device used for the analysis of a notched micro beam specimen under three-point loading will be presented. The objective of this study was to investigate the effect of geometric configuration on the stress field around singularity for a micro beam specimen by asymptotic, numerical and probabilistic analysis. The scope of work is fourfold. First, the effect of notch angle on the strength of the singularity is determined using two different asymptotic analysis methods — complex potential method and Airy stress function method. Second, the effect of the angular variation (for different notch angle) on the influence coefficients is determined using analytical methods. Third, the effect of the notch angle and depth on the stress intensity factor is determined using finite element methods and contour integral method. Fourth, the probabilistic analysis of maximum stress developed in the micro beam specimen is performed.
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Baleri, M., F. Sassani, and P. L. Ko. "Stick-Slip Vibration Between Two Large Concentric Circular Discs in Rotational Contact With Multiple Point Loads." In STLE/ASME 2003 International Joint Tribology Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/2003-trib-0263.
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This paper presents a study of the stick-slip frictional phenomenon when large contact areas subjected to uneven contact loads are involved. The objective of the investigation is to gain better understanding of the phenomenon from experimental observations and to develop a mathematical representation that can be used for modeling, simulation and design purposes. A dynamic integral-model has been proposed and simulations have been carried out. The effects of various system parameters on the behavior of the system have been studied experimentally and analytically. The simulation results using the proposed integral-model are in good agreement with the experimental results. The latter also show that stick-slip vibrations can be influenced by the loading conditions.
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Zhu, Danhui, Hualing Chen, Xiangjie Kong, and Wenbo Zhang. "A New Hybrid Method for Mid-Frequency Vibration of Beam-Plate System Under External Point Loading." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-63168.
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In this paper, a new hybrid method combining finite element analysis (FEA) and energy finite element analysis (EFEA) is developed for predicting the vibrational response of beam-plate system in mid-frequency range, which enables the local detailed response of the system to be obtained. The waves produced in the system exhibit low- and high-frequency vibrational characteristics simultaneously, which are called stiff member and flexible member separately. The former is modeled using classical FEA, meanwhile the latter is simulated by EFEA. However, unlike classical EFEA, the vibrational energy is considered as the superposition of the direct field and the reverberant field associating the mechanism of wave propagation in high-frequency. Furthermore, the power transfer between two fields is considered according to the transferring pathway analysis of power flow, which is more accurate than the traditional EFEA at the driving points and boundaries. Additionally, the compatibility of the stiff and flexible members is formulated in a global matrix of the system, in which the interactions between these two members are captured. The new developments are validated by a beam-plate system with a line junction under an external point loading applied on the beam, and good correlations are found when compared with the results from very dense classical FEA model.
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Heaney, Patrick S., and Onur Bilgen. "A Multi-Point Loaded Piezocomposite Beam: Mechanics and Response to Harmonic Excitation." In ASME 2018 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/smasis2018-7940.
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In this paper a multi-segment beam, in what is called an inertial four-point loaded configuration, is proposed and its dynamic response is analyzed. In this configuration, two symmetrical overhanging free segments extend beyond the pinned supports, and two tip masses are attached to these free segments yielding symmetrical inertial loading at the tips. By varying the configuration parameters of this multi-segment beam, such as support locations and tip loading, the dynamic response of the system can be significantly altered. The harmonically excited transverse vibration of a piezocomposite beam with four-point loaded boundary conditions is analyzed as a function of the support location and tip mass. Experimental data for several support locations is presented for validation of the analytical model and the predicted relationship between the system natural frequency, support locations, and tip masses. Comparisons are also made between the multi-point loaded cases and a reference cantilevered beam. The analytical and experimental results demonstrate that the natural frequency of a multi-point loaded beam can be continuously adjusted in a relatively wide range using the configuration changes investigated.
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Kamel, Merhane, and Khalid Al Shehhi. "VOC Recovery System for Crude Oil Tanker Loading." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/210906-ms.
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Abstract During offshore and onshore loading of crude oil tankers, huge volumes of valuable Volatile Organic Compounds (VOC) are emitted to the atmosphere maybe up to 330 ton per Very Large Crude Oil Carrier (VLCC). When these emissions are liquified, they will be equal to hundreds of barrels of oil. They are a substantial source of financial loss and destructive environmental impact. The objective of this paper is to introduce a Vapor Recovery System concept which can limit & recover the emissions of VOC up to 90% at the Fujairah Terminal. All loading and unloading of oil on offshore, on Floating Storage Offloading Unit (FSOs) and Floating Production Storage Offloading (FPSOs), on onshore storage tanks and terminals, and on shuttle tankers contribute to significant emissions of VOCs. It is possible to install Vapor Recovery Unit (VRU) on each of these applications to capture and recover VOCs. There are two generic approaches to VOC recovery, known as ‘Active’ and ‘Passive’ VOC recovery technology. The Active Vapor Recovery Unit VRU systems typically include a compression step followed by condensation, absorption and/or adsorption. The Passive VRU systems use vapor-balanced loading/unloading with VOC as blanket gas for storage vessels. The VOCs are a combination of Methane and Non-Methane components which evaporate from crude oil and are typically vented into the atmosphere during routine ship loading activities, causing emissions of harmful vapor to the environment. These vapors also represent a fire/explosion hazard. The methodology will be to apply a new concept to limit and recover the VOC emissions during loading of crude oil tankers alongside a Single Point Mooring (SPM). The VOC recovery technology is a unique combination of a modern offshore Supply Vessel (OSV) which considers both hydrocarbon recovery as well as power generation.
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Selvan, Veera, Virginia Halls, James Zheng, and Namas Chandra. "Comparing the Behavior of Homogeneous vs. Fluid Filled Solid Headforms Under Blunt Impact Loading Conditions." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64971.
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A single point acceleration measurement at the center of gravity (C.G) of the rigid headform has been typically used to assess the head injuries under the blunt loading conditions. The head protective equipment (e.g. Helmets) used in sports, vehicles and defense fields are developed and tested based on this single point acceleration. This raises two critical questions; 1) can a homogeneous rigid headform represent the heterogeneous skull-brain complex; 2) If not, which is the critical point of measurement in the compliant headform. To answer these questions, compliant (acrylic gel complex) and rigid (aluminum body) head surrogates with an identical mass are subjected to similar blunt loading conditions. Target surfaces of different stiffness and an impact velocity of 1 m/s are employed to evaluate the critical difference in the head surrogates. Acceleration (C.G) and shell strain (impact location) in the compliant surrogate and acceleration (C.G) and the impact force in the rigid surrogate are experimentally measured. Experimental and computational studies illustrate that the acceleration field in the gel-filled case varies from coup to counter-coup region; however, the acceleration field in the rigid headform is uniform. The variation in the acceleration field is influenced by the shell deformation that in turn depends on the stiffness of the target surface. In deformable target surfaces, the acceleration and head injury criterion (HIC) values are higher in the compliant surrogate than the rigid surrogate; the effect is reversed for rigid target surfaces.
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Duffey, Thomas A., and Derek Doyle. "Plastic Instabilities in Spherical Shells Under Load, Displacement, and Impulsive Loading." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93727.
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Plastic instabilities that could potentially develop in spherical shells under a variety of symmetric loading conditions are examined. First, a literature survey of both static and dynamic instabilities associated with spherical shells is presented, with emphasis on plastic tensile instability. Then, building upon work done elsewhere for cylindrical shells, a plastic instability condition for spherical shells subjected to displacement controlled and impulsive loading is developed and compared with earlier results reported in the literature. It is found that the instability point for displacement controlled loading and impulsive loading of a spherical shell is the same as for a uniaxial tension specimen and for an impulsively loaded plane-strain ring/cylinder. In addition, a simple, one-dimensional strain-softening model is developed that investigates the relationship between instabilities associated with displacement-controlled loading and impulsive loading. Conclusions of this work are that there are two fundamental types of instabilities associated with failure of spherical shells: local and global. Moreover, the local instability, associated with failure under displacement control and impulsive loading, is found to require an imperfection to develop, whereas the global instability does not require an imperfection. The need for experiments to verify these results is discussed.
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Nakasuji, Yoshizumi, Hiroyuki Iwasaki, and Hiroaki Sakai. "Room-Temperature Strength of Sintered Silicon Nitride Subjected to High-Temperature Creep Loading." In ASME 1994 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/94-gt-280.
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Room-temperature strength was evaluated using sintered silicon nitride crept specimens. Creep tests were performed using 4-point bending loading at 1400°C in air. The bending creep tests applied stresses from 100 to 400 MPa for 10−1 to 3×103 hours. For applied stress over 200 MPa, the room-temperature strength of the crept specimen had two stages. In the first stage the strength degraded slowly, and in the second stage the strength degraded rapidly. In the first stage, oxidation caused the strength degradation, since the degradation was similar for the different applied stresses. In the second stage, large creep deformation mainly caused the strength degradation. Early in the stage, creep induced matrix and boundary damage under the oxidation layer caused the degradation. At the end of the stage, cracks induced by creep caused the degradation.
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Karadağ, Huseyin, and Seyhan Firat. "The response of flexible pavement roads to loading frequency." In 7th International Conference on Road and Rail Infrastructure. University of Zagreb Faculty of Civil Engineering, 2022. http://dx.doi.org/10.5592/co/cetra.2022.1468.
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Traffic load is one of the main factors that cause permanent deformation in the pavement, which is an important factor specifying road life and serviceability related to traffic safety. In addition to truck axle load level, deformation level in road pavement depends on superstructure materials, subgrade conditions, climate, groundwater conditions, number of load repetitions, and loading frequency. Loading frequency affects both the deformation level in pavement layers and the stress state. In this study, the effect of loading speed (loading frequency) was evaluated by carrying out a finite element analysis of certain flexible road pavement cross-sections under 400 kPa pressure. A triangular load pulse with 400 kPa was loaded on pavement cross-sections with different loading speeds. The analyzed cross-section of flexible road pavement consists of asphalt concrete layer, unbound base, and subbase layers. Subgrade material is the clay layer. For dynamic analyses of road pavement under the repetitive load of different loading speeds, 2D axial symmetric analyses were performed. The Hardening Soil Model with Small Strain Stiffness (HSsmall) soil model was used for modeling unbound granular layers and subgrade soil. Asphalt concrete was modeled with the Mohr-Coulomb material model. The tire contact area was assumed as a square area within 300 mm side length. Loading pulse durations were calculated for different loading speeds. The analyses show that the total vertical deformation for the analyzed section has a minimum value of 90 km/h loading Speed (6.94 Hz). As the loading speed increases or decreases, the total vertical deformation of the cross-section on either side of this point increases. The deformation graph has two local maximum points because of the resonance of the pavement system. These results are consistent with previous studies. Results show that controlling the loading speed will lengthen the road serviceability life by reducing the deformation.
Reports on the topic "Two-point loading"
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Patel, Reena. Complex network analysis for early detection of failure mechanisms in resilient bio-structures. Engineer Research and Development Center (U.S.), June 2021. http://dx.doi.org/10.21079/11681/41042.
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Bio-structures owe their remarkable mechanical properties to their hierarchical geometrical arrangement as well as heterogeneous material properties. This dissertation presents an integrated, interdisciplinary approach that employs computational mechanics combined with flow network analysis to gain fundamental insights into the failure mechanisms of high performance, light-weight, structured composites by examining the stress flow patterns formed in the nascent stages of loading for the rostrum of the paddlefish. The data required for the flow network analysis was generated from the finite element analysis of the rostrum. The flow network was weighted based on the parameter of interest, which is stress in the current study. The changing kinematics of the structural system was provided as input to the algorithm that computes the minimum-cut of the flow network. The proposed approach was verified using two classical problems three- and four-point bending of a simply-supported concrete beam. The current study also addresses the methodology used to prepare data in an appropriate format for a seamless transition from finite element binary database files to the abstract mathematical domain needed for the network flow analysis. A robust, platform-independent procedure was developed that efficiently handles the large datasets produced by the finite element simulations. Results from computational mechanics using Abaqus and complex network analysis are presented.
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Stakes, Keith, and Joseph Willi. Study of the Fire Service Training Environment: Safety, Fidelity, and Exposure -- Acquired Structures. UL Firefighter Safety Research Institute, March 2019. http://dx.doi.org/10.54206/102376/ceci9490.
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Previous FSRI led research projects have focused on examining the fire environment with regards to current building construction methods, synthetic fuel loading, and best-practices in firefighting strategies and tactics. More than 50 experiments have been previously conducted utilizing furniture to produce vent-limited fire conditions, replicating the residential fire environment, and studying the methods of horizontal ventilation, vertical ventilation, and positive pressure attack. Tactical considerations generated from the research are intended to provide fire departments with information to evaluate their standard operating procedures and make improvements, if necessary, to increase the safety and effectiveness of firefighting crews. Unfortunately, there still exists a long standing disconnect between live-fire training and the fireground as evident by continued line of duty injury and death investigations that point directly to a lack of realistic yet safe training, which highlights a continued misunderstanding of fire dynamics within structures. The main objective of the Study of the Fire Service Training Environment: Safety, Fidelity, and Exposure is to evaluate training methods and fuel packages in several different structures commonly used across the fire service to provide and highlight considerations to increase both safety and fidelity. This report is focused on the evaluation of live-fire training in acquired structures. A full scale structure was constructed using a similar floor plan as in the research projects for horizontal ventilation, vertical ventilation, and positive pressure attack to provide a comparison between the modern fire environment and the training ground. The structure was instrumented which allowed for the quantification of fire behavior, the impact of various ventilation tactics, and provided the ability to directly compare these experiments with the previous research. Twelve full scale fire experiments were conducted within the test structure using two common training fuel packages: 1) pallets, and 2) pallets and oriented strand board (OSB). To compare the training fuels to modern furnishings, the experiments conducted were designed to replicate both fire and ventilation location as well as event timing to the previous research. Horizontal ventilation, vertical ventilation, and positive pressure attack methods were tested, examining the proximity of the vent location to the fire (near vs. far). Each ventilation configuration in this series was tested twice with one of the two training fuel loads. The quantification of the differences between modern furnishings and wood-based training fuel loads and the impact of different ventilation tactics is documented through a detailed comparison to the tactical fireground considerations from the previous research studies. The experiments were compared to identify how the type of fuel used in acquired structures impacts the safety and fidelity of live-fire training. The comparisons in this report characterized initial fire growth, the propensity for the fire to become ventilation limited, the fires response to ventilation, and peak thermal exposure to students and instructors. Comparisons examined components of both functional and physical fidelity. Video footage was used to assess the visual cues, a component of the fire environment that is often difficult to replicate in training due to fuel load restrictions. The thermal environment within the structure was compared between fuel packages with regards to the potential tenability for both students and instructors.
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AN ANALYTICAL METHOD FOR EVALUATING THE DEFLECTION AND LOAD-BEARING AND ENERGY ABSORPTION CAPACITY OF ROCKFALL RING NETS CONSIDERING MULTIFACTOR INFLUENCE. The Hong Kong Institute of Steel Construction, September 2022. http://dx.doi.org/10.18057/ijasc.2022.18.3.1.
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In this study, an analytical method for evaluating the structural performance, including maximum deflection, load-bearing, and energy absorption capacity of a steel wire-ring net, was proposed to effectively design the ring net of the flexible barrier systems. Puncture tests of the ring nets and two-point traction tests of the three-ring chains with various wire-ring specifications were conducted. Correlation analysis was used to test the results between ring nets and chains, revealing that three structural performance indicators of the test specimens were strongly related. The ring net’s structural performance was affected specifically by ring chains on the shortest load transfer path. Accordingly, a three-ring chain with a flexible boundary corresponded to a fibre–spring element. A three-dimensional analytical model of the ring net was established. Explicit formulas for computing the three indicators of the ring net were derived. Comprehensive quasi-static and impact tests, using different shapes and sizes of punching devices, were conducted, providing valuable data to calibrate and validate this analytical method. The ability of the model in yielding consistent results when implemented at the structure scale was then assessed, based on the data of full-scale impact tests on a 1500kJ-energy rockfall barrier. Lastly, the effects of various factors, such as single ring geometry, the length–width ratio of the net, loading area size, boundary stiffness, and load rate, influencing the structural performance indicators of the ring net were investigated, respectively.