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Investigation of the Capabilities of Yield Functions on Describing the Deformation Behavior of 5754O Aluminum Alloy Sheet Under combined loading Paths

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Journal of Shanghai Jiaotong university(Science) 2016年第5期21卷 562-568页

作者：王海波刘艳福陈正阳万敏聂红争 School of Mechanical and Materials Engineering North China University of Technology School of Mechanical Engineering and Automation Beihang University

The combined loading tests of 5754 O aluminum alloy sheet are used to verify the yield function. Three yield functions are implemented into the commercial finite element model(FEM) code ABAQUS as a user material subroutine UMAT for the FEM simulation of the combined loading tests. The comparison of the simulating and experimental results shows that the modified Yld2000-2d yield function can describe the mechanical behavior of5754 O aluminum alloy sheet under combined loading paths reasonably while other three yield functions do *** performance of the modified Yld2000-2d yield function on describing the mechanical behavior under combined loading paths is analyzed in detail. It is concluded that the modified Yld2000-2d yield function can be adopted to describe the deformation behavior of 5754 O aluminum alloy sheet for industrial applications.

关键词： aluminum alloy sheet combined loading yield function finite element model(FEM)

Study on Failure Mechanism and Bearing Capacity of Three-Dimensional Rectangular Footing Subjected to combined loading

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China Ocean Engineering 2008年第2期22卷 313-330页

作者：张其一栾茂田王忠涛 State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology

This paper presents two kinematic failure mechanisms of threc-dimensional rectangular footing resting on homogeneous undrained clay foundation under uniaxial vertical loading and uniaxial moment loading. The failure mechanism under vertical loading comprises a plane strain Prandti-type mechanism over the central part of the longer side, and the size of the mechanism gradually reduces at the ends of the longer side and over the shorter side as the corner of rectangular footing is being approached where the direction of soil motion remains normal to each corresponding side respectively. The failure mechanism under moment loading comprises a plane strain scoop sliding mechanism over the central part of the longer side, and the radius of scoop sliding mechanism increases linearly at the ends of the longer side. On the basis of the kinematic failure mechanisms mentioned above, the vertical ultimate bearing capacity and the ultimate bearing capacity against moment or moment ultimate bearing capacity are obtained by use of upper bound limit analysis theory. At the same time, numerical analysis results, Skempton＇ s results and Salgado et al. ＇s results are compared with this upper bound solution. It shows that the presented failure mechanisms and plastic limit analysis predictions are validated. In order to investigate the behaviors of undrained clay foundation beneath the rectangular footing subjected to the combined loadings, numerical analysis is adopted by virtue of the general-purpose FEM software ABAQUS, where the clay is assumed to obey the Mohr-Coulomb yielding criterion. The failure envelope and the ultimate bearing capacity are achieved by the numerical analysis results with the varying aspect ratios from length L to breadth B of the rectangular footing. The failure mechanisms of rectangular footing which are subjected to the combined vertical loading V and horizontal loading H （Vertical loading V and moment loading M, and horizontal loading H and moment loading M

关键词： rectangular footing upper bound limit analysis failure mechardsm failure envelope combined loading

Modified Coffin-Manson equation to predict the fatigue life of structural materials subjected to mechanical-thermal coupling non-coaxial loading

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Journal of Materials Science & Technology 2023年第29期160卷 118-127页

作者： Zhichao Ma Chaofan Li Wei Zhang Shenghui Wang Jiakai Li Hongwei Zhao Luquan Ren School of Mechanical and Aerospace Engineering Jilin UniversityChangchun 130025China Key Laboratory of CNC Equipment Reliability Ministry of EducationJilin UniversityChangchun 130025China Key Laboratory of Bionic Engineering Ministry of Education Jilin UniversityChangchun 130025China

With regard to the structures subjected to severe mechanical-thermal coupling fatigue conditions,the consistency between service conditions and loading conditions was the prerequisite for the fatigue prop-erties test and fatigue life prediction.A miniature piezoelectric-driven instrument integrating with a tripodal piezoelectric actuator and envelope-type heating function was developed to investigate the mechanical-thermal coupling fatigue properties and obtain the fatigue life of materials under approximate service conditions.A physical model was described to quantitatively calculate the alternating deformation under the mechanical-thermal coupling tensile-bending combined ***,a fatigue life prediction method based on the Coffin-Manson equation under tensile-bending combined loading was proposed to estimate the mechanical-thermal coupling fatigue life in terms of the total coupling defor-mation and plastic strain *** feasibility of the proposed instrument was verified through the analysis of displacement responses of high entropy alloy specimens under the thermal-mechanical cou-pling tensile-bending combined condition at temperatures ranging from RT to 600°*** comparison between fatigue lives directly measured through thermal-mechanical coupling experiments and theoreti-cally predicted fatigue lives indicated the availability of the modified Coffin-Manson equation.

关键词： Fatigue testing instrument Mechanical-thermal coupling combined loading Fatigue life prediction odified Coffin-Manson equation

Failure Loci of Suction Caisson Foundations Under combinedloading Conditions

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China Ocean Engineering 2008年第3期22卷 455-464页

作者：王栋金霞 State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology College of Computer Science and Technology Dalian Maritime University

Suction caissons are widely used to support offshore fixed platforms in coastal areas. The loadings transferred to suction caissons include the eccentric lateral force induced by waves and self weight of the platform structure. However, under this kind of combined loading conditions, the failure mechanism of caissons with shallow embedment depths is quite different from conventional deep foundations or onshore shallow footings. The behaviour of caissons subjected to combined loadings may be described with the ＂failure locus＂ in force resultant spaces. Here the failure loci of smooth caissons are studied by use of finite dement approach, with the embedment ratio of caissons varying in the range of 0.25 - 1.0 and eccentricity ratio of horizontal loadiugs in 0 - 10. The platform settlement and tilt limits are involved into determination of failure loci, thus the platforms can avoid significant displacements for the combined loadings located inside the failure locus. Three families of loading paths are used to map out the locus. It is found that the shape of failure loci depends on 3 non-dimensional parameters, and the failure locus of a given caisson changes gradually from the elliptical curve to hooked curve with increasing shear strength of soil. The lateral capacity of short caissons may be enhanced by vertical forces, compared with the maximum lateral capacity of long caissons occurring at the vertical force being zero. The critical embedment ratios partitioning elliptical and hooked loci are proposed.

关键词： suction caissons finite elements clays bearing capacity combined loading

combined load bearing capacity of rigid piles embedded in a crossanisotropic clay deposit using 3D finite element lower bound

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第3期15卷 717-737页

作者： Ardavan Izadi Reza Jamshidi Chenari Department of Civil Engineering Faculty of EngineeringUniversity of GuilanRashtGuilanIran

In this study,an iterative-based three-dimensional finite element lower bound in association with the second-order cone programming method is adopted to evaluate the limit load of a single pile embedded in cross-anisotropic soils under general loading *** lower bound solutions of the pile embedded in an anisotropic soil deposit can be found by formulating the element equilibrium,equilibrium of shear and normal stresses along discontinuities,boundary conditions,yield function,and optimizing the objective function through the second-order cone programming method in conjunction with an iterative-based update procedure.A general loading condition is considered to profile the expansion of the safe load in the vertical-horizontal-moment(V-H-M)*** results of this study are compared and validated against three different cases including an isotropic lateral loading,anisotropic end bearing capacity,and a pile embedded in an isotropic soil deposit under general loading condition.A parametric study is conducted to evaluate the impact of different influencing *** was found that the effect of anisotropy on the variation of lateral limit load of a single pile is more pronounced than the corresponding vertical and bending moment limit loads,whereas the interface properties have more significant effects on the vertical and bending moment limit loads in comparison to the lateral limit load.

关键词： Rigid pile Cross-anisotropy Clay combined loading Three-dimensional finite element lower bound

Establishing the need to model the actual state of stress along rock bolts

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International Journal of Mining Science and Technology 2020年第3期30卷 279-286页

作者： Prasoon Singh AJS(Sam)Spearing K.V.Jessu Pâmmela Caroline Pinazzi da Silva Ribeiro Curtin University KalgoorlieWA 6430Australia

Proper design of rock bolt support in underground mines is critical to avoid incidents, accidents and loss of production. The traditional design approach only considers the axial(tensile) capacity and this is clearly not the situation in situ, where a rock bolt is subjected to both axial and shear/bending loads which determines its overall performance and failure behaviour. To demonstrate and analyse the shear displacement in bedded roof, scaled physical models of underground excavation were created. From the models it was found that the shear displacement between the layers depends on the vertical roof deformation and thickness of beds. To analyse the effect of combined loading on rock bolt design for suspension and beam building models, analytical methods were used to calculate the required spacing of rock bolt for a given safety factor. Numerical models were then created using Rocscience RS2 software to establish the stresses on the rock bolt. The results show a significant reduction in safety factor for suspension as demonstrated in an example(reduced from 3.5 to 2.0) and beam building(2.0 to 1.36) when the rock bolt capacities are calculated considering the effect of combined loading as opposed to just the axial or shear loads.

关键词： combined loading Rock bolt Suspension model Beam building model Numerical modelling Analytical methods

POSTBUCKLING OF IMPERFECT STIFFENED CYLINDRICAL SHELLS UNDER combined EXTERNAL PRESSURE AND HEATING

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Applied Mathematics and Mechanics(English Edition) 1998年第5期19卷 411-423页

作者：沈惠申 Department of Civil Engineering Shanghai Jiaotong University Shanghai P. R. China

A postbuckling analysis is presented for a stiffened cylindrical shell of finite length subjected to combined loading of external pressure and a uniform temperature rise. The formulations are based on a boundary layer theory of shell buckling, which includes the effects of nonlinear prebuckling deformations, nonlinear large deflections in the postbuckling range and initial geometrical imperfections of the shell. The 'smeared stiffener' approach is adopted for the stiffeners. The analysis uses a singular perturbation technique to determine the interactive buckling loads and the postbuckling equilibrium paths. Numerical examples cover the performances of perfect and imperfect, stringer and ring stiffened cylindrical shells. Typical results are presented in dimensionless graphical form.

关键词： postbuckling thermal postbuckling stiffened cylindrical shell combined loading a boundary layer theory of shell buckling singular perturbation technique

Postbuckling of Imperfect Stiffened Cylindrical Shells Under combined External Liquid Pressure and Axial Compression

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China Ocean Engineering 1996年第4期11卷 367-390页

作者： Shen HuishenProfessor, Department of Civil Engineering. Shanghai Jiao Tong University. Shanghai 200030 Department of Civil Engineering Shanghai Jiao Tong University Shanghai 200030

posthuckling analysis is presented for the stilTened cylindrical shell of finite length subjected to combined loading of external liquid pressure and axial compression. The formulations are based on a boundary layer theory of shell buckling, which includes the effects of nonlinear prebuckling deformations, nonlinear large deflections in the postbuckling range and initial geometrical imperfections of the shell. The 'smeared stifl'cner' approach is adopted for the stiffencrs. In the analysis a singular perturbation technique is used (o determine the interactive buckling loads and the postbuckling paths. Numerical examples cover the performance of perfect and imperfect, stringer and ring stiffened cylindrical shells. Typical results arc presented in the dimcnsionless graphical form.

关键词： structural stability ptwtbuckling stiffened cylindrical shell combined loading boundary layer theory of shell buckling singular perturbation technique.