Engineering members often include cutouts.Although the structural integrity of such members can be highly influenced by associated stresses,determining them may be very challenging for finite shapes operating in an in...Engineering members often include cutouts.Although the structural integrity of such members can be highly influenced by associated stresses,determining them may be very challenging for finite shapes operating in an industrial environment.This is particularly so if the loading is not well known,a common occurrence in practical situations.While photomechanical methods can be effective,they necessitate optical access to the component,something which is also often unavailable.Recognizing the above,this paper demonstrates ability to determine the complete stresses throughout a perforated tensile plate using only aligned,single-element strain gages rather than multi-element rosettes.Although reliability is verified using finite elements,an objective of the technique is for situations when finite element methods are not feasible,e.g.,the loading is inadequately known.The approach is applicable to members fabricated from isotropic,orthotropic or functionally-graded materials and is not restricted to a particular shape,cutout arrangement or loading condition.展开更多
This paper presents the results of finite element analysis of rubber structures based on novel strain energy functions stemming from the representation theorem of tensorial function. The stress tensor is represented b...This paper presents the results of finite element analysis of rubber structures based on novel strain energy functions stemming from the representation theorem of tensorial function. The stress tensor is represented by Taylor expansion, using the representation theorem of tensorial function of a single tensorial argument for all terms in each order of the expansion. The scalar-valued coefficient functions of the theorem are represented by the integrity bases of the strain tensor and material constants to be determined by experiment. The computer implementation of the new constitutive laws has been verified by comparing the FE results with analytical solutions. A complicated structure of rubber bearing was analyzed. The FE results show good correlation with experimental data.展开更多
The seismic loading on saturated soil deposits induces a decrease in effective stress and a rearrangement of the soil-particle structure, which may both lead to a degradation in undrained stiffness and strength of soi...The seismic loading on saturated soil deposits induces a decrease in effective stress and a rearrangement of the soil-particle structure, which may both lead to a degradation in undrained stiffness and strength of soils. Only the effective stress influence on small strain shear modulus Gmax is considered in seismic response analysis nowadays, and the cyclic shearing induced fabric changes of the soil-particle structure are neglected. In this paper, undrained cyclic triaxial tests were conducted on saturated sands with the shear wave velocity measured by bender element, to study the influences of seismic loading on Gmax. And Gmax of samples without cyclic loading effects was also investigated for comparison. The test results indicated that Gmax under cyclic loading effects is lower than that without such effects at the same effective stress, and also well correlated with the effective stress variation. Hence it is necessary to reinvestigate the determination of Gmax in seismic response analysis carefully to predict the ground responses during earthquake more reasonably.展开更多
文摘Engineering members often include cutouts.Although the structural integrity of such members can be highly influenced by associated stresses,determining them may be very challenging for finite shapes operating in an industrial environment.This is particularly so if the loading is not well known,a common occurrence in practical situations.While photomechanical methods can be effective,they necessitate optical access to the component,something which is also often unavailable.Recognizing the above,this paper demonstrates ability to determine the complete stresses throughout a perforated tensile plate using only aligned,single-element strain gages rather than multi-element rosettes.Although reliability is verified using finite elements,an objective of the technique is for situations when finite element methods are not feasible,e.g.,the loading is inadequately known.The approach is applicable to members fabricated from isotropic,orthotropic or functionally-graded materials and is not restricted to a particular shape,cutout arrangement or loading condition.
文摘This paper presents the results of finite element analysis of rubber structures based on novel strain energy functions stemming from the representation theorem of tensorial function. The stress tensor is represented by Taylor expansion, using the representation theorem of tensorial function of a single tensorial argument for all terms in each order of the expansion. The scalar-valued coefficient functions of the theorem are represented by the integrity bases of the strain tensor and material constants to be determined by experiment. The computer implementation of the new constitutive laws has been verified by comparing the FE results with analytical solutions. A complicated structure of rubber bearing was analyzed. The FE results show good correlation with experimental data.
基金Project supported by the National Natural Science Foundation ofChina (No. 10372089) and Provincial Department of EducationZhejiang Province (No. 20010572) China
文摘The seismic loading on saturated soil deposits induces a decrease in effective stress and a rearrangement of the soil-particle structure, which may both lead to a degradation in undrained stiffness and strength of soils. Only the effective stress influence on small strain shear modulus Gmax is considered in seismic response analysis nowadays, and the cyclic shearing induced fabric changes of the soil-particle structure are neglected. In this paper, undrained cyclic triaxial tests were conducted on saturated sands with the shear wave velocity measured by bender element, to study the influences of seismic loading on Gmax. And Gmax of samples without cyclic loading effects was also investigated for comparison. The test results indicated that Gmax under cyclic loading effects is lower than that without such effects at the same effective stress, and also well correlated with the effective stress variation. Hence it is necessary to reinvestigate the determination of Gmax in seismic response analysis carefully to predict the ground responses during earthquake more reasonably.
