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作者： Guo Yingnan,Zheng Xitao ,Wu Ling ,Sun Qin,Chai Yanan School of Aeronautics, Northwestern Polytechnic University, Xi''an 710072 , China Aircraft Strength Research Institute, Xi''an 710065, China

＜正＞A combined test and numerical study has been conducted for the failure analysis of three-dimensional （3D） four-directional braided composite lugs. The objective of the study was to get information on the stiffness, strength and failure mode of the lug, as well as on the applicability of the analysis method used to predict lug load response and failure. The 3D braided joints with two different geometries were tested under pin loading to evaluate the effects of the joint geometry on the failure load and mode. The test lugs were manufactured with the resin transfer molding （RTM） technique. The test specimens were loaded parallel to the lug centerline. The analyses were performed using finite element method. Shell element was used. failure was estimated on the characteristic curve using the Yamada - Sun criteria. The measured strains showed fairly good correlation with the analysis results. It can be concluded that with correct material properties the FE approach used in the analyses can provide a reasonable estimate for the load response and failure of 3D braided composite lugs

关键词： Composites 3D Braided Lug failure load FEM

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Hierarchical models for failure analysis of plates bent by distributed and localized transverse loadings

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第5期9卷 600-613页

作者： Erasmo CARRERA Gaetano GIUNTA Aeronautic and Space Engineering Department Politecnico di Torino Torino Italy

The failure analysis of simply supported, isotropic, square plates is addressed. Attention focuses on minimum failure load amplitudes and failure locations, von Mises＇ equivalent stress along the plate thickness is also addressed. Several distributed and localized loading conditions are considered. loads act on the top of the plate. Bi-sinusoidal and uniform loads are taken into account for distributed loadings, while stepwise constant centric and off-centric loadings are addressed in the case of localized loadings. Analysis is performed considering plates whose length-to-thickness ratio a/h can be as high as 100 （thin plates） and as low as 2 （very thick plates）. Results are obtained via several 2D plate models. Classical theories （CTs） and higher order models are applied. Those theories are based on polynomial approximation of the displacement field. Among the higher order theories （HOTs） HOTsa models account for the transverse shear deformations, while HOTs models account for both transverse shear and transverse normal deformations. LHOTs represent a local application of the higher order theories. A layerwise approach is thus assumed： by means of mathematical interfaces, the plate is considered to be made of several fictitious layers. The exact 3D solution is presented in order to determine the accuracy of the results obtained via the 2D models. In this way a hierarchy among the 2D theories is established. CTs provide highly accurate results for a/h greater than 10 in the case of distributed loadings and greater than 20 for localized loadings. Results obtained via HOTs are highly accurate in the case of very thick plates for bi-sinusoidal and centric loadings. In the case of uniform and off-centric loadings a high gradient is present in the neighborhood of the plate top. In those cases, LHOTs yield results that match the exact solution.

关键词： failure load von Mises' equivalent stress lsotropic plates Higher order theories (HOTs) Exact 3D solution

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Stress analysis of clamped-free grid composite cylindrical shell under various end loadings

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Journal of Central South University 2014年第7期21卷 2667-2672页

作者： ARASHMEHR JAFAR RAHIMI GHOLAMHOSSEIN RASOULI FAZEL Mechanical Engineering Department Tarbiat Modares University

Stress analysis of cylindrical grid-stiffened composite shells was conducted under transverse loading,pure bending,torsion and axial compression under clamped-free boundary *** strain gauges were employed to measure the strains in transverse loading case to validate the finite element analysis which was conducted using ANSYS *** agreement was obtained between the two *** was observed that stiffening the composite shell with helical ribs decreased the average equivalent Von Mises stress on the *** reduction of the stress seemed to be higher in the intersection of two *** was also seen that the stress reduction ratio was higher when the structure was under bending compared to torsion and axial *** reduction ratio was approximately 75% in pure bending in the intersection point of the ribs,while it was approximately 25% in ***,it is concluded that the presence of the ribs is more effective under *** analysis was done using Tsai-Wu *** ribs were observed to result in maximum and minimum increase in the failure load of the structure under transverse bending and torsional loading,respectively.

关键词： stiffened composite shell end loading stress analysis failure load

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Mechanical behavior of colonic anastomosis in experimental settings as a measure of wound repair and tissue integrity

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World Journal of Gastroenterology 2006年第35期12卷 5668-5673页

作者： Konstantinos A Ekmektzoglou Georgios C Zografos Stavros K Kourkoulis Ismene A Dontas Panagiotis K Giannopoulos Κaterina A Marinou Maria V Poulakou Despina N Perrea Laboratory of Experimental Sur- gery and Surgical Research "NS Christeas" University of Athens Medical School Athens Greece 1st Univer- sity Department of General Surgery Athens School of Medicine Hippocration Hospital Athens Greece Laboratory of Testing and Materials De- partment of Mechanics National Technical University of Athens Greece BVMS MVM Laboratory of Experimen- tal Surgery and Surgical Research "NS Christeas" University of Athens Medical School Athens Greece and Greek Ministry of Rural Development and Food General Directorate of Veterinary Services

AIM: To determine the mechanical properties of anasto- motic colonic tissue in experimental settings and there- fore give a measure of wound healing. METHODS: Thirty-six male Wistar rats were used as ex- perimental models of anastomotic tissue integrity. On the 5th post-operative day, the tensile strength was measured by application of an axial force, providing a quantitative measure of anastomotic dehiscence and leakage. RESULTS: Diagrams of the load as a function of the time [P = P (t)] and of the displacement also as a func- tion of time [Δs = Δs (t)] were recorded for each test, permitting the design of the load versus the displace- ment diagram and thus providing significant data about the critical values of anastomotic failure. Quantitative data were obtained concerning the anastomotic strength of both control specimens (healthy rats), as well as spec- imens from non-healthy rats for comparison. CONCLUSION: This experimental model provides an excellent method of measuring anastomotic strength. Despite the relative small number of specimens used, this method provides an accurate way of measuring wound repair. More experimental measurements need to be performed to correlate emerging tensile strength val-ues to anastomotic failure.

关键词： Mechanical behavior failure load Colon Anastomosis Wound healing

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Flexural Behavior of Cross-Connected Brick Masonry Infill Wall Panels Supported on Reinforced Concrete Beam Grids

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Journal of Shanghai Jiaotong university(Science) 2024年第5期29卷 889-899页

作者： BAYOUMI El-Said Abd-Allah MAHMOUD Mahmoud Hassan ARIF Mohammed Department of Civil Engineering College of EngineeringQassim UniversityBuraidah51452Saudi Arabia Engineering Expert at Ministry of Justice Cairo11516Egypt Department of Civil Engineering Faculty of EngineeringAl-Azhar UniversityCairo11651Egypt Department of Civil Engineering Aligarh Muslim UniversityAligarh202002India

This paper presents an experimental investigation on the flexural behavior of cross-connected brick masonry infill wall panels supported on reinforced concrete beam grids above and below the *** experimental program was comprised of six wall *** effect of change in lower beam stiffness relative to the wall and the geometry of the main walls were *** the results of the experimental tests,the increase in the depth of the lower beam grid reduces the deflection,resulting in an increase in the load carrying capacity of the ***,the stiffness of the main walls affects the deflection and the failure load of the cross walls.

关键词： brick masonry infill walls reinforced concrete beam grid main and cross walls stiffness deflection crack pattern failure load

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Experimental study on load bearing behavior of large-scaled caps with pile groups

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Engineering Sciences 2009年第3期7卷 78-83页

作者： Guo Chao Lu Bo Gong Weiming Qiu Hongxing Department of Civil Engineering Southeast University Nanjing 210096 China Quality Supervision Station of Rizhao Planning and Urban Construction Committee Shandong Rizhao 276826 China

The objective of this investigation was to study the behavior of deep pile caps and the ultimate load-carrying capacity. Four 1/10 scaled models of nine-pile caps were cast and tested on vertical loads to failure. The destruction shapes of pile caps,the correlation between load and displacement,and the internal stresses were analyzed systematically. The results demonstrated that the failures of all the four models are resulted from punching shear; the internal flow of the forces in nine-pile caps can be approximated by "strut-and-tie" model. Furthermore,the failure loads of these specimens were predicted by some of the present design methods and the calculated results were compared with the experimental loads. The comparative results also indicated that the "strut-and-tie" model is a more reasonable design method for deep pile caps design.

关键词： large-scaled caps with pile groups punching shear strut-and-tie model failure load

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