scholarly journals Effective strain criterion under multimode and multiaxial loadings – A rubber S–N curve with the scatter-band factor of 1.6 from 90 fatigue cases

2022 ◽  
Vol 16 (2) ◽  
pp. 130-141
Author(s):  
Robert Keqi Luo
Keyword(s):  
Effective Strain ◽  
Strain Criterion ◽  
Multiaxial Loadings

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

scholarly journals An Extension Strain Type Mohr–Coulomb Criterion

2021 ◽  
Author(s):  
Manfred Staat
Keyword(s):  
Failure Modes ◽  
Peak Stress ◽  
Fracture Initiation ◽  
Failure Surface ◽  
Confining Pressure ◽  
Biaxial Compression ◽  
Simple Extension ◽  
Strain Criterion ◽  
Shear Component ◽  
Extension Strain

AbstractExtension fractures are typical for the deformation under low or no confining pressure. They can be explained by a phenomenological extension strain failure criterion. In the past, a simple empirical criterion for fracture initiation in brittle rock has been developed. In this article, it is shown that the simple extension strain criterion makes unrealistic strength predictions in biaxial compression and tension. To overcome this major limitation, a new extension strain criterion is proposed by adding a weighted principal shear component to the simple criterion. The shear weight is chosen, such that the enriched extension strain criterion represents the same failure surface as the Mohr–Coulomb (MC) criterion. Thus, the MC criterion has been derived as an extension strain criterion predicting extension failure modes, which are unexpected in the classical understanding of the failure of cohesive-frictional materials. In progressive damage of rock, the most likely fracture direction is orthogonal to the maximum extension strain leading to dilatancy. The enriched extension strain criterion is proposed as a threshold surface for crack initiation CI and crack damage CD and as a failure surface at peak stress CP. Different from compressive loading, tensile loading requires only a limited number of critical cracks to cause failure. Therefore, for tensile stresses, the failure criteria must be modified somehow, possibly by a cut-off corresponding to the CI stress. Examples show that the enriched extension strain criterion predicts much lower volumes of damaged rock mass compared to the simple extension strain criterion.

scholarly journals 3D-FEM Simulation of Hot Rolling Process and Characterization of the Resultant Microstructure of a Light-Weight Mn Steel

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 569
Author(s):  
Ana Claudia González-Castillo ◽  
José de Jesús Cruz-Rivera ◽  
Mitsuo Osvaldo Ramos-Azpeitia ◽  
Pedro Garnica-González ◽  
Carlos Gamaliel Garay-Reyes ◽  
...  
Keyword(s):  
Hot Rolling ◽  
Thermomechanical Processing ◽  
Computational Simulation ◽  
Effective Strain ◽  
Fem Simulation ◽  
Rolling Process ◽  
3D Fem ◽  
Hot Rolling Process ◽  
Mn Steel

Computational simulation has become more important in the design of thermomechanical processing since it allows the optimization of associated parameters such as temperature, stresses, strains and phase transformations. This work presents the results of the three-dimensional Finite Element Method (FEM) simulation of the hot rolling process of a medium Mn steel using DEFORM-3D software. Temperature and effective strain distribution in the surface and center of the sheet were analyzed for different rolling passes; also the change in damage factor was evaluated. According to the hot rolling simulation results, experimental hot rolling parameters were established in order to obtain the desired microstructure avoiding the presence of ferrite precipitation during the process. The microstructural characterization of the hot rolled steel was carried out using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the phases present in the steel after hot rolling are austenite and α′-martensite. Additionally, to understand the mechanical behavior, tensile tests were performed and concluded that this new steel can be catalogued in the third automotive generation.

scholarly journals The impact of drilling and slitting construction on damage field: evolution characteristics in low-permeability coal seam

2021 ◽  
Vol 37 ◽  
pp. 205-215
Author(s):  
Heng Chen ◽  
Hongmei Cheng ◽  
Aibin Xu ◽  
Yi Xue ◽  
Weihong Peng
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Damage Mechanics ◽  
Effective Strain ◽  
Secondary Development ◽  
Distribution Area ◽  
Finite Element Program ◽  
Element Program ◽  
Mining Face ◽  
The Impact

ABSTRACT The fracture field of coal and rock mass is the main channel for gas migration and accumulation. Exploring the evolution law of fracture field of coal and rock mass under the condition of drilling and slitting construction has important theoretical significance for guiding efficient gas drainage. The generation and evolution process of coal and rock fissures is also the development and accumulation process of its damage. Therefore, based on damage mechanics and finite element theory, the mathematical model is established. The damage variable of coal mass is defined by effective strain, the elastoplastic damage constitutive equation is established and the secondary development of finite element program is completed by FORTRAN language. Using this program, the numerical simulation of drilling and slitting construction of the 15-14120 mining face of Pingdingshan No. 8 Mine is carried out, and the effects of different single borehole diameters, different kerf widths and different kerf heights on the distribution area of surrounding coal fracture field and the degree of damage are studied quantitatively. These provide a theoretical basis for the reasonable determination of the slitting and drilling arrangement parameters at the engineering site.

A Version of the Failure Criterion Modification for Plane Concrete

2017 ◽  
Vol 755 ◽  
pp. 300-321 ◽  
Author(s):  
Volodymyr I. Korsun ◽  
Yu.Yu. Kalmykov ◽  
S.Yu. Makarenko
Keyword(s):  
Comparative Analysis ◽  
Solid Mechanics ◽  
Concrete Strength ◽  
Failure Criteria ◽  
Analytic Description ◽  
Deformable Solid ◽  
Theoretical Approaches ◽  
Concrete Failure ◽  
Stress States ◽  
Multiaxial Loadings

The paper is about the generally accepted in the deformable solid mechanics principles of constructing limiting surfaces of concrete strength in the principal stress space. The background and theoretical approaches taken by different researchers to describe the functions of deviatoric and meridional curves as the basic elements which determine the surface configuration of concrete strength were analyzed.There was carried out a comparative analysis of different authors’ suggestions on an analytic description of concrete strength for different stress states and a comparison of the developed criteria and the results of short-term tests of plane concrete under multiaxial loadings. Comparing the methods taken for developing the interpolation functions of deviatoric and meridional curves, it was inferred that the application of different approaches to the development of concrete failure criteria is effective. Keeping in mind the results of the comparative analysis of the prerequisites taken to develop the above failure criteria and the requirements of a better approximation of the experimental data, there are made new suggestions to describe concrete strength for the general case of stress state.

Bending and Twisting of Pipes With Strain Hardening

1984 ◽  
Vol 106 (2) ◽  
pp. 188-195 ◽  
Author(s):  
J. H. Lau ◽  
T. T. Lau
Keyword(s):  
Effective Strain ◽  
Closed Form Solution ◽  
Bending Moment ◽  
Small Deformation ◽  
Form Solution ◽  
Simultaneous Action ◽  
Deformation Analysis ◽  
Engineering Practice ◽  
Strain Diagram ◽  
Interaction Curves

A closed-form solution is presented for the small deformation analysis of a straight thin-walled circular cylinder subjected to the simultaneous action of bending and twisting moments. Dimensionless interaction curves and charts which relate the variables, bending moment, curvature, maximum effective strain, twisting moment, and shear strain are also provided for engineering practice convenience. The average stress-strain diagram of the cylinder is described by two straight lines. The result presented herein is not only a good approximation of a wide class of piping materials, but also provides a standard tool for estimating the accuracy of different direct schemes such as numerical integration, finite-difference, and finite-element methods.

Sign in / Sign up

Export Citation Format

Share Document