scholarly journals Analytical Prediction of Stretch-Bending Springback Based on the Proportional Kinematic Hardening Model

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2389
Author(s):  
Ruixue Zhai ◽  
Zhuangkun Zhao ◽  
Jianhao Yang ◽  
Bangbang Ma ◽  
Gaochao Yu
Keyword(s):  
Kinematic Hardening ◽  
Bending Moment ◽  
Material Model ◽  
Loading Path ◽  
Curvature Radius ◽  
Analytical Prediction ◽  
Hardening Model ◽  
Stretch Bending ◽  
Analytic Expressions ◽  
Loading Methods

Pre-stretching and post-bending are the simplest loading methods for the profile stretch-bending technical process. The inner layers of the profile are stretched and then compressed during the loading process. Considering the Bauschinger effect of metal materials, a new material model called the proportional kinematic hardening model was proposed. The stretch-bending mechanical model was established under a pre-stretching and post-bending loading path. The stress and strain on the cross section of profiles were analyzed. The analytic expressions of curvature radius of the strain neutral layer and bending moment were derived after loading. The analytic method for determining the curvature radius of the geometric center layer after unloading and springback during stretch-bending was established. The rectangular section ST12 profile with symmetrical characteristics is adopted, the stretch-bending experimental results show that the new proportional kinematic hardening model is more accurate than the classical kinematic hardening model in predicting the stretch-bending springback.

Effect of Yield Surface Curvature on Local Necking in Biaxially Stretched Sheets in Porous Materials

1992 ◽  
Vol 114 (2) ◽  
pp. 196-200 ◽  
Author(s):  
Xiangqiao Yan
Keyword(s):  
Porous Materials ◽  
Yield Surface ◽  
Kinematic Hardening ◽  
Material Model ◽  
Isotropic Hardening ◽  
Material Models ◽  
Hardening Model ◽  
Local Necking ◽  
Highly Sensitive ◽  
Isotropic Expansion

In this paper, a recently proposed material model (Sun model) that is based on the lower bound approach of plasticity is extended by introducing a family of dilatant plasticity theories. The yield surfaces change by a combination of isotropic expansion and kinematic translation. The sensitivity of the local necking predictions in biaxially stretched sheets to the curvature of the yield surface in porous materials is addressed. The results of the present analysis obtained by using four material models, the isotropic hardening version of Sun, the kinematic hardening version suggested in this paper, the Gurson model, and the Mear and Hutchinson model, indicate that the local necking predictions are highly sensitive to the curvature of the yield surface, and the predictions given by the kinematic hardening model are more reasonable for local necking analysis than those by the isotropic hardening model.

scholarly journals Springback Prediction of Aluminum Alloy Sheet under Changing Loading Paths with Consideration of the Influence of Kinematic Hardening and Ductile Damage

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 950 ◽  
Author(s):  
Zhenming Yue ◽  
Jiashuo Qi ◽  
Xiaodi Zhao ◽  
Houssem Badreddine ◽  
Jun Gao ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Sheet Metal ◽  
Kinematic Hardening ◽  
Material Model ◽  
Alloy Sheet ◽  
Ductile Damage ◽  
Loading Path ◽  
Aluminum Alloy Sheet ◽  
Strain Paths ◽  
Springback Prediction

Springback prediction of sheet metal forming is always an important issue in the industry, because it greatly affects the final shape of the product. The accuracy of simulation prediction depends on not only the forming condition but also the chosen material model, which determines the stress and strain redistributions in the formed parts. In this paper, a newly proposed elastoplastic constitutive model is used, in which the initial and induced anisotropies, combined nonlinear isotropic and kinematic hardenings, as well as isotropic ductile damage, are taken into account. The aluminum alloy sheet metal AA7055 was chosen as the studied material. In order to investigate springback under non-proportional strain paths, three-point bending tests were conducted with pre-strained specimens, and five different pre-straining states were considered. The comparisons between numerical and experimental results highlighted the hard effect of both kinematic hardening and ductile damage on the springback prediction, especially for a changed loading path case.

Correlation of Test and FEA Studies on Effect of Bend Radius and Thickness on Ratcheting in Pipe Bends Subjected to Internal Pressure and In-Plane Bending Moment

2005 ◽  
Author(s):  
K. Shanmuga Sundaran ◽  
G. Thanigaiyarasu
Keyword(s):  
Internal Pressure ◽  
Analytical Study ◽  
Kinematic Hardening ◽  
Bending Moment ◽  
Material Model ◽  
Analysis Procedure ◽  
Strain Accumulation ◽  
Bend Radius ◽  
Plane Bending ◽  
Selection Of

The paper deals with the results from the analytical study on ratcheting in pipe bends. There has been no well-defined material model and analysis procedure to predict this phenomenon accurately. A recent development in parameter selection of Chaboche’s Kinematic hardening model has resulted in close predictions in ratcheting analysis [15]. A problem has been selected from existing experimental results [16, 17] published in literature, and an analysis incorporating these parameters has been carried out and presented. The amount of stresses induced and strain accumulated in pipe bends with long and short radius and subjected to internal pressure and in-plane bending moment is studied. The results and their inferences are included. The analysis was carried out on 2-inch NPS SS304 pipe bends with different bend radius and two thickness (Schedule 40 and Schedule 80) using ABAQUS, non-linear FEA software to predict the strain accumulation and their influences on ratcheting failure is presented.

scholarly journals Investigation of Seismic Behavior of Clay-Pile Using Nonlinear Kinematic Hardening Model

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Mohsen Saleh Asheghabadi ◽  
Xiaohui Cheng
Keyword(s):  
Seismic Behavior ◽  
Kinematic Hardening ◽  
Bending Moment ◽  
Pile Group ◽  
Triaxial Tests ◽  
Model Parameters ◽  
Elastic Model ◽  
Cyclic Shear ◽  
Hardening Model ◽  
Calibration Methods

In geotechnical mediums where the bearing capacity of upper layers of soil is not suitable for use of the shallow foundations, piles are usually used as deep foundations to transfer loads to the stronger lower layers. Here, the seismic behavior of single pile and pile group constructed in saturated soft kaolin clay under three different earthquakes using Abacus 3D software is investigated. The aluminum material considering the linear elastic model has been used for the piles, and the nonlinear kinematic hardening model with Von Mises failure criterion has been considered for clay. This model can consider the soil stiffness degradation by increasing the number of cyclic loading. Three different methods have been used to calibrate the model parameters, two of them are new methods. In all calibration methods, the cyclic shear and undrained cyclic triaxial tests are used. The results obtained from the numerical analysis of the soil-pile model are in relatively good agreement with the centrifuge model results. According to the results, the variation of earthquake frequency and intensity affects the bending moment created along the pile and also the distance between piles in a pile group affects the amount of the interaction between them.

scholarly journals Numerical Simulations and Experimental Study on the Reeling Process of Submarine Pipeline by R-Lay Method

2021 ◽  
Vol 9 (6) ◽  
pp. 579
Author(s):  
Ming Ju ◽  
Xiaodong Xing ◽  
Liquan Wang ◽  
Feihong Yun ◽  
Xiangyu Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Kinematic Hardening ◽  
Bending Moment ◽  
Material Model ◽  
Element Model ◽  
Structural Instability ◽  
Thickness Ratio ◽  
Combined Loading ◽  
Obvious Effect ◽  
Von Mises Plasticity

During the reeling process of the reel-lay method, the pipe will be subjected to combined loading of tension and bending. Excessive ovalization of the pipe will affect the structural performance and even lead to structural instability of the pipe. In this paper, a numerical simulation model of the pipe-reeling process is established by finite element tools. The Ramberg–Osgood material model is used to study the ovalization and bending moment of the pipe cross-section during the pipe-reeling process based on the Von Mises plasticity and nonlinear kinematic hardening rules. The results show that the ovalization and bending moment of the pipe section will change significantly during the pipe-reeling process. Subsequently, one set of 6-inch pipe-reeling experimental setups was designed to conduct a full-scale experiment. Compared with the experimental results, the feasibility of the finite element model is verified. Finally, the effects of diameter-to-thickness ratio, the material parameters of the pipe, and the pipe axial tension on the ovalization and bending moment changes are studied. Research shows that each parameter has a certain influence on the pipe of the reeling process, and the diameter-to-thickness ratio of the pipe has the most obvious effect. When the diameter-to-thickness ratio decreases, the bearing capacity for bending moments and the ability to resist ovalization of pipe are enhanced. At the same time, each parameter has a significant impact on the reeling process of the pipeline.

Numerical Modeling and Analytical Investigation of Autofrettage Process on the Fluid End Module of Fracture Pumps

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Mahdi Kiani ◽  
Roger Walker ◽  
Saman Babaeidarabad
Keyword(s):  
Residual Stresses ◽  
Kinematic Hardening ◽  
Analytical Formula ◽  
Strain Analysis ◽  
Material Model ◽  
Analytical Investigation ◽  
Stress Strain ◽  
Element Analysis ◽  
Hardening Material ◽  
Strain Evolution

One of the most important components in the hydraulic fracturing is a type of positive-displacement-reciprocating-pumps known as a fracture pump. The fluid end module of the pump is prone to failure due to unconventional drilling impacts of the fracking. The basis of the fluid end module can be attributed to cross bores. Stress concentration locations appear at the bores intersections and as a result of cyclic pressures failures occur. Autofrettage is one of the common technologies to enhance the fatigue resistance of the fluid end module through imposing the compressive residual stresses. However, evaluating the stress–strain evolution during the autofrettage and approximating the residual stresses are vital factors. Fluid end module geometry is complex and there is no straightforward analytical solution for prediction of the residual stresses induced by autofrettage. Finite element analysis (FEA) can be applied to simulate the autofrettage and investigate the stress–strain evolution and residual stress fields. Therefore, a nonlinear kinematic hardening material model was developed and calibrated to simulate the autofrettage process on a typical commercial triplex fluid end module. Moreover, the results were compared to a linear kinematic hardening model and a 6–12% difference between two models was observed for compressive residual hoop stress at different cross bore corners. However, implementing nonlinear FEA for solving the complicated problems is computationally expensive and time-consuming. Thus, the comparison between nonlinear FEA and a proposed analytical formula based on the notch strain analysis for a cross bore was performed and the accuracy of the analytical model was evaluated.

scholarly journals Modification of the Johnson–Cook Material Model for Improved Simulation of Hard Milling High-Performance Steel Components

2021 ◽  
Vol 2 (3) ◽  
pp. 571-580
Author(s):  
Andrey Vovk ◽  
Amin Pourkaveh Dehkordi ◽  
Rainer Glüge ◽  
Bernhard Karpuschewski ◽  
Jens Sölter
Keyword(s):  
High Performance ◽  
Kinematic Hardening ◽  
Material Model ◽  
Detailed Knowledge ◽  
Hard Milling ◽  
Bending Tests ◽  
Finite Element Software ◽  
Steel Material ◽  
Finish Cutting ◽  
Cutting Processes

Understanding the effect of thermomechanical loads during finish cutting processes, in our case hard milling, on the surface integrity of the workpiece is crucial for the creation of defined quality characteristics of high-performance components. Compared to computationally generated modifications by simulation, the measurement-based determination of material modifications can only be carried out selectively and on a point-by-point basis. In practice, however, detailed knowledge of the changes in material properties at arbitrary points of the high-performance component is of great interest. In this paper, a modification of the well-known Johnson–Cook material model using the finite element software Abaqus is presented. Special attention was paid to the kinematic hardening behavior of the used steel material. Cyclic loads are relevant for the chip formation simulation because, during milling, after each cut, the material under the surface is loaded plastically several times and not necessarily in the same direction. Therefore, in analogy, multiple bending was investigated on samples made of 42CrMo4. A pronounced Bauschinger effect was observed in the bending tests. An adaptation of the material model to the results of the bending tests was only possible to a limited extent without kinematic hardening, which is why the Johnson–Cook model was supplemented by the Armstrong–Frederick hardening approach. The modified Johnson–Cook–Armstrong–Frederick material model was developed for practical use as a VUMAT and verified by bending tests for simulation use.

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