scholarly journals The Effect of Void Arrangement on the Pattern Transformation of Porous Soft Solids under Biaxial Loading

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1205
Author(s):  
Hai Qiu ◽  
Ying Li ◽  
Tianfu Guo ◽  
Shan Tang ◽  
Zhaoqian Xie ◽  
...  
Keyword(s):  
Biaxial Loading ◽  
Tensile Deformation ◽  
Biaxial Stress ◽  
Porous Solids ◽  
Biaxial Compression ◽  
Structural Topology ◽  
Soft Solids ◽  
Tension And Compression ◽  
Inclined Angle ◽  
Pattern Transformation

Structural topology and loading condition have important influences on the mechanical behaviors of porous soft solids. The porous solids are usually set to be under uniaxial tension or compression. Only a few studies have considered the biaxial loads, especially the combined loads of tension and compression. In this study, porous soft solids with oblique and square lattices of circular voids under biaxial loadings were studied through integrated experiments and numerical simulations. For the soft solids with oblique lattices of circular voids, we found a new pattern transformation under biaxial compression, which has alternating elliptic voids with an inclined angle. This kind of pattern transformation is rarely reported under uniaxial compression. Introducing tensile deformation in one direction can hamper this kind of pattern transformation under biaxial loading. For the soft solids with square lattices of voids, the number of voids cannot change their deformation behaviors qualitatively, but quantitatively. In general, our present results demonstrate that void morphology and biaxial loading can be harnessed to tune the pattern transformations of porous soft solids under large deformation. This discovery offers a new avenue for designing the void morphology of soft solids for controlling their deformation patterns under a specific biaxial stress-state.

Deformation and pattern transformation of porous soft solids under biaxial loading: Experiments and simulations

2018 ◽  
Vol 20 ◽  
pp. 81-90 ◽  
Author(s):  
Hai Qiu ◽  
Ying Li ◽  
Tian Fu Guo ◽  
Xu Guo ◽  
Shan Tang
Keyword(s):  
Biaxial Loading ◽  
Soft Solids ◽  
Pattern Transformation

scholarly journals Approximate Biaxial Stress Solution for Orthotropic Open-Hole Composite Laminates

1996 ◽  
Vol 5 (4) ◽  
pp. 096369359600500
Author(s):  
C. Filiou ◽  
C. Soutis
Keyword(s):  
Approximate Solution ◽  
Stress Distribution ◽  
Circular Hole ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Biaxial Loading ◽  
Biaxial Stress ◽  
Orthotropic Composite ◽  
Open Hole ◽  
Simple Approximate Solution

A simple approximate solution has been derived for the stress distribution near a circular hole applicable to any orthotropic composite laminate subjected to biaxial loading. The degree of accuracy of this solution was found to be overall acceptable, but strongly dependent upon the laminate lay-up and biaxiality ratio.

The Biaxial Stress-Strain Curves of Sheet Metals

2010 ◽  
Vol 44-47 ◽  
pp. 2519-2523
Author(s):  
Hai Bo Wang ◽  
Min Wan ◽  
Yu Yan ◽  
Xiang Dong Wu
Keyword(s):  
Transverse Direction ◽  
Biaxial Loading ◽  
Testing Machine ◽  
Rolling Direction ◽  
Biaxial Stress ◽  
Loading Path ◽  
Sheet Metals ◽  
Stress Strain ◽  
Loading Paths ◽  
Loading Ratio

Biaxial tensile tests of 5754O aluminum alloy sheet and B170P1 steel sheet were performed under linear loading paths with cruciform specimens and a biaxial loading testing machine. The stress-strain curves under different loading paths were obtained. It is found that the loading path has a significant influence on the stress-strain curves, i.e., the stress-strain curves vary with the loading path. The stress-strain curves in the rolling direction become higher with the decrease of the loading ratio (the ratio of the load along the rolling direction to that along the transverse direction) from 4:0 to 4:4. Meanwhile the stress-strain curves in the transverse direction become lower with the decrease of the loading ratio from 4:4 to 0:4. Based on Yld2000-2d yield criterion, the experimental phenomena of the two kinds of sheet metals under biaxial tension were explained theoretically.

Thermoplasticity model for concrete under transient temperature and biaxial stress

1992 ◽  
Vol 439 (1905) ◽  
pp. 59-80 ◽  
Keyword(s):  
Biaxial Loading ◽  
Elevated Temperatures ◽  
Biaxial Stress ◽  
Rate Equations ◽  
Sustained Load ◽  
Integration Scheme ◽  
Transient Temperature ◽  
Hardening Material ◽  
Perfectly Plastic ◽  
Nonlinear Hardening

In the past, the theory of thermoplasticity has been confined to metal type materials exhibiting an elastic-perfectly-plastic behaviour. This paper describes the application of this theory to modelling the response of a nonlinear hardening material (concrete in the present case) under transient temperature and stress. The difficulties arising from the application of the theory of thermoelastoplasticity to modelling the behaviour of concrete at elevated temperatures are discussed, together with the inadequacy of the existing algorithms that were proposed for perfectly plastic materials, to cope with a nonlinear hardening case. An integration scheme derived from the Euler backward scheme is used to integrate the rate equations. The resulting model is used to analyse existing biaxial data and investigate the effect of a sustained load on the deformational response of concrete under biaxial loading and elevated temperature.

Analysis and Simulation of Elastic-Plastic Fracture Parameters at Crack Tip under Biaxial Loading and Uniaxial Loading

2012 ◽  
Vol 166-169 ◽  
pp. 2883-2886 ◽  
Author(s):  
Zhong Xian Wang ◽  
Rui Liu
Keyword(s):  
Biaxial Loading ◽  
Crack Tip ◽  
Tensile Specimen ◽  
Biaxial Stress ◽  
Fracture Parameter ◽  
Single Edge ◽  
Elastic Plastic ◽  
Finite Distance ◽  
Fracture Theory ◽  
Loading Modes

Based on the J-A2 two-parameter elastic-plastic fracture theory and finite element numerical method, the elastic-plastic stress field ahead of the crack tip in a single edge cracked eccentric tensile specimen (the load-line is at a finite distance from the crack tip) was analyzed and compared with that of a center cracked large plate under biaxial loading. By using the Ritchie-Knott-Rice fracture criterion, a transformational relation between the two loading modes was obtained based on the J-A2 equivalent principle. As a result, the fracture parameter determined from a single edge cracked eccentric tensile specimen can be applied to the fracture analysis of a center cracked plate under biaxial stress.

Ultimate Capacity Behavior of Pitted Mild Steel Plates Under Biaxial Compression

2011 ◽  
Author(s):  
Xiaoli Jiang ◽  
C. Guedes Soares
Keyword(s):  
Mild Steel ◽  
Biaxial Loading ◽  
Fem Analysis ◽  
Steel Plates ◽  
Dominant Factor ◽  
Biaxial Compression ◽  
Ultimate Capacity ◽  
Thickness Loss ◽  
Loading Ratio ◽  
Corrosion Pits

The aim of the present paper is to investigate the effects of corrosion pits on the ultimate capacity of rectangular mild steel plates under biaxial compression. A series of non-linear FEM analysis on plates with partial depth pits are carried out, changing geometrical attributes of both pits and plates, i.e., the radius, depth, location and distribution of the pits and the slenderness of the plates. Possible interaction between transverse and longitudinal axial compression is studied applying different level of loading ratio and considering the effects of partial depth pitting corrosion. It is shown that biaxial loading ratio is a dominant factor affecting the behavior of pitted plates besides pits intensity and thickness loss at pits. When longitudinal compression is dominant load with loading ratio lower than 1, the interaction relationship curves for different DOP levels tend to be parallel with each other and the distance between every two parallel curves seems to be dependent mainly on the deviation of their DOP values and thickness loss at pits. Moreover, pits distribution along long and shirt edges could also affect the ultimate strength behavior of plates. The work done in the paper illustrates that the ultimate capacity of pitted plate could be derived from intact plate by introducing important influential parameters like DOP, thickness loss and possible pits distribution.

scholarly journals An Experimental Evaluation of Plasticity Theories for Anisotropic Metals

1971 ◽  
Vol 38 (1) ◽  
pp. 15-22 ◽  
Author(s):  
R. M. W. Frederking ◽  
O. M. Sidebottom
Keyword(s):  
Biaxial Loading ◽  
Plastic Region ◽  
Axial Direction ◽  
Compression Tests ◽  
Anisotropic Plasticity ◽  
Deformation Curves ◽  
Biaxial Tests ◽  
Tension And Compression ◽  
Experimental Yield ◽  
Good Agreement

An experimental investigation was undertaken to evaluate anisotropic plasticity theories which have been proposed in the literature. Three different metals in the form of 2.5-in-dia bars were considered: SAE 1020 steel preloaded in tension to a strain of 8 percent, copper alloy 360 (free-cutting brass) preloaded in tension to a strain of 3 percent, and 2024-T351 aluminum alloy as received. All metals had approximately the same properties in the radial and circumferential directions with greatly different properties in the axial direction. Tension and compression tests were conducted on specimens having directions of axial, circumferential, and 45 deg to the axis. Hollow torsion tests were conducted on axial specimens. Biaxial tests were conducted on thin-walled cylinders. All loading was monotonic and proportionate and extended well into the plastic region. Anisotropic plasticity theories were evaluated by comparing theoretical and experimental yield curves for each material and by comparing theoretical load-deformation curves with experimentally determined curves for tension and compression specimens at 45 deg to the axis, for hollow torsion specimens, and for biaxial loading. In most cases, good agreement was found between theory and experiment.

Ratchetting Behavior of Primary Heat Transport (PHT) Piping Material SA-333 Carbon Steel Subjected to Cyclic Loads at Room Temperature

2004 ◽  
Author(s):  
Sandeep Kulkarni ◽  
Y. M. Desai ◽  
T. Kant ◽  
G. R. Reddy ◽  
C. Gupta ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Heat Transport ◽  
Biaxial Loading ◽  
Experimental Results ◽  
Biaxial Stress ◽  
Mean Stress ◽  
Bending Load ◽  
Chaboche Model ◽  
Stress Ratios ◽  
Uniaxial And Biaxial Loading

Ratchetting behavior of SA-333 Gr. 6 carbon steel used as primary heat transport (PHT) piping material has been investigated with three constitutive models proposed by Armstrong-Frederick, Chaboche and Ohno-Wang involving different hardening rules. Performance of the above mentioned models have been evaluated for a broad set of uniaxial and biaxial loading histories. The uniaxial ratchetting simulations have been performed for a range of stress ratios (R) by imposing different stress amplitudes and mean stress conditions. Numerical simulations indicated significant ratchetting and opening of hysteresis loop for negative stress ratio with constant mean stress. Application of cyclic stress without mean stress (R = −1.0) has been observed to produce negligible ratchet-strain accumulation in the material. Simulation under the biaxial stress condition was based on modeling of an internally pressurized thin walled pipe subjected to cyclic bending load. Numerical results have been validated with the experiments as per simulation conditions. All three models have been found to predict the observed accumulation of circumferential strain with increasing number of cycles. However, the Armstrong Frederick (A-F) model was found to be inadequate in simulating the ratchetting response for both uniaxial as well as biaxial loading cases. The A-F model actually overpredicted the ratchetting strain in comparison with the experimental strain values. On the other hand, results obtained with the Chaboche and the Ohno-Wang models for both the uniaxial as well as biaxial loading histories have been observed to closely simulate the experimental results. The Ohno-Wang model resulted in better simulation for the presents sets of experimental results in comparison with the Chaboche model. It can be concluded that the Ohno-Wang model suited well compared to the Chaboche model for above sets of uniaxial and biaxial loading histories.

scholarly journals Mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0246815
Author(s):  
Honggang Zhao ◽  
Haitao Sun ◽  
Dongming Zhang ◽  
Chao Liu
Keyword(s):  
Mechanical Properties ◽  
Failure Mode ◽  
Failure Modes ◽  
Biaxial Stress ◽  
Tensile Fracture ◽  
Biaxial Compression ◽  
Lateral Stress ◽  
Variable Theory ◽  
Failure Characteristics ◽  
Elliptical Opening

Two kinds of common tunnel shapes, i.e. elliptical opening and square opening were selected for biaxial compression tests, and the influences of two kinds of opening shapes on the mechanical properties, failure characteristics and failure modes of sandstone were compared and analyzed. The complex variable theory and mapping functions were used to obtain the analytical stress solution around elliptical and square openings. The results show that the stability of the specimen containing an elliptical opening was better than that of the specimen containing a square opening under the same lateral stress. Compared with the elliptical opening, the local damage was formed earlier in the square opening which might be caused by a higher stress concentration around the square opening. The stress distributions around openings were influenced by the opening shape and lateral stress coefficient. The top and bottom of square opening were more prone to tensile fracture, and the distribution range of tensile was larger than that of elliptical opening. When the opening failed, the intensity of square opening failure was weaker than that of elliptical opening. On the basis of the average frequency value and the rise angle value, the failure mode of specimen containing elliptical or square opening was distinguished. It was found that the mixed tension and shear failure dominated the failure of specimens with different opening shapes, and the number of shear cracks in the specimen containing a square opening was greater than that in the specimen containing an elliptical opening. The above method of judging failure mode by acoustic emission signals was well verified by the CT images of damaged specimens.

Experimental Investigation of Spontaneous Buckling-Driven Delamination of Thin Films on Soft Spherical Substrate

2019 ◽  
Author(s):  
Yusaku Saito ◽  
Shuhei Yoshioka ◽  
Kanako Emori ◽  
Brenda Teoh Rui Ern ◽  
Akio Yonezu
Keyword(s):  
Spherical Shell ◽  
Biaxial Loading ◽  
Radial Strain ◽  
Air Pressure ◽  
Surface Strain ◽  
Biaxial Compression ◽  
Bulge Test ◽  
Pdms Substrate ◽  
Pdms Film ◽  
Surface Buckling

Abstract This study develops a new experimental system to investigate surface buckling patterns that emerge due to the biaxial compression of elastomeric bilayer spherical shell. The sample used in this study is a thick PDMS (polydimethylsiloxane) substrate and a thin PDMS film. In order to induce biaxial strain to the surface of PDMS substrate, air pressured device like bulge test is first developed. This system enables a flat PDMS plate to isotropically expand and become a hemisphere due to air pressure. In other words, the surface of PDMS substrate is stretched and subjected to biaxial loading. Subsequently, a thin PDMS film is covered on the hemisphere substrate. By releasing the air pressure, the pre-stretch in the substrate is released gradually and the outer film is subjected to biaxial compression. During the biaxial compression, various film buckling patterns are observed. It is found that the surface buckling patterns are wrinkle formation that is associated with film delamination. This formation pattern is dependent on the surface strain distribution, i.e. radial strain and circumferential strain. In order to control the pattern of buckling-delamination, we systematically changed the material parameters, such as the film thickness, Young’s modulus, interfacial fracture toughness, etc. Our experiment is capable in reproducing various wrinkle patterns with film delamination on an elastomeric bilayer spherical shell.

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