scholarly journals The Dahl’s Model for the Inelastic Bending Behavior of Textile Composite Preforms. Analysis of its Influence in Draping Simulation

2021 ◽  
Vol 8 ◽  
Author(s):  
Théo A. Ghafour ◽  
Julien Colmars ◽  
Philippe Boisse
Keyword(s):  
Friction Model ◽  
Inelastic Behavior ◽  
Textile Composite ◽  
Forming Process ◽  
Shell Elements ◽  
Forming Simulation ◽  
Bending Behavior ◽  
Woven Reinforcement ◽  
The One ◽  
Continuous Material

Most of the numerical simulations of dry textile reinforcements forming are based on a macroscopic approach and continuous material models whose behavior is assumed to be elastic (linear or nonlinear). On the one hand, the experience shows that under loading/unloading stresses, residual inelastic deformations are observed. On the other hand, among the deformations that a woven reinforcement undergoes during forming, in most cases, only bending is subject to loading/unloading stresses. The first objective of this work is to highlight the inelastic bending behavior of textile reinforcements during a forming process and to find the possible origins of inelasticity. The second objective is to find the cases generating bending loading/unloading during forming as well as to study the influence of the bending inelasticity on forming simulation. For this purpose, the inelastic bending behavior was characterized by three-point bending tests. Then, the Dahl friction model was adapted to bending to describe the inelastic behavior. Finally, this model was implemented in a finite element code based on shell elements allowing the study of the influence of taking into account the inelastic behavior in bending on the numerical simulation of forming.

Flow Stress Models Analysis for Metal Powder Forming Simulation

2013 ◽  
Vol 690-693 ◽  
pp. 2331-2335
Author(s):  
Ming Jun Liu ◽  
Hua Ping Chen ◽  
Jun Xia Jiang
Keyword(s):  
Flow Stress ◽  
Yield Criterion ◽  
Three Dimensional ◽  
Forming Process ◽  
Forming Simulation ◽  
Mechanical Models ◽  
Powder Forming ◽  
Stress Models ◽  
Continuous Material ◽  
Matrix Powder

Powder forming process can produce parts with homogeneous and satisfactory mechanical properties. Based on the assumption that the powder system is a compressive continuous material, the flow stress models used in powder forming were analyzed. The correspondent elasto-plastic constitutive model was derived from the yield criterion. Appropriate algorithm and mechanical models were applied. The program was developed and three-dimensional simulations for the powder compaction process of the iron matrix powder were performed. Effects of different flow stress models on simulation results were analyzed.

Thermoforming Simulation of Multilayer Composites with Continuous Fibre and Thermoplastic Matrix

2014 ◽  
Vol 611-612 ◽  
pp. 368-374
Author(s):  
Eduardo Guzman Maldonado ◽  
Nahiene Hamila ◽  
Philippe Boisse ◽  
Philippe Chaudet
Keyword(s):  
Friction Model ◽  
Contact Friction ◽  
Thermoplastic Resin ◽  
Forming Process ◽  
Plane Shear ◽  
Shell Elements ◽  
Continuous Fibre ◽  
Thermoplastic Matrix ◽  
Different Temperatures ◽  
Thermoforming Process

CFRTP prepreg laminates thermoforming (Continuous Fibre Reinforcements and Thermoplastic Resin) is a fast composite manufacturing process. Furthermore the thermoplastic matrix is favourable to recycling. The development of a thermoforming process is complex and expensive to achieve by trial/error. A simulation approach for thermoforming of multilayer thermoplastic is presented. Each prepreg layer is modelled by semi-discrete shell elements. These elements consider the tension, in-plane shear and bending behaviour of the ply at different temperatures around the fusion point. The contact/friction during the forming process is taken into account using forward increment Lagrange multipliers. A lubricated friction model is implemented between the layers and for ply/tool friction. Thermal and forming simulations are presented and compared to experimental results. The computed shear angles after forming and wrinkles are in good agreement with the thermoforming experiment.

Application of the Radial Return Method to Compute Stress Increments From Mroz’s Hardening Rule

2000 ◽  
Vol 123 (4) ◽  
pp. 398-402 ◽  
Author(s):  
Sing C. Tang ◽  
Z. Cedric Xia ◽  
Feng Ren
Keyword(s):  
Metal Forming ◽  
Computing Time ◽  
Isotropic Hardening ◽  
Stress Increment ◽  
Anisotropic Hardening ◽  
Forming Process ◽  
Shell Elements ◽  
Hardening Rule ◽  
Metal Forming Process ◽  
Return Method

It is well known in the literature that the isotropic hardening rule in plasticity is not realistic for handling plastic deformation in a simulation of a full sheet-metal forming process including springback. An anisotropic hardening rule proposed by Mroz is more realistic. For an accurate computation of the stress increment for a given strain increment by using Mroz’s rule, the conventional subinterval integration takes excessive computing time. This paper proposes the radial return method to compute such stress increment for saving computing time. Two numerical examples show the efficiency of the proposed method. Even for a sheet model with more than 10,000 thin shell elements, the radial return method takes only 40 percent of the overall computing time by the subinterval integration.

Topology Optimization of Blank Geometry for the Sheet Forming Process

2012 ◽  
Author(s):  
Saber DorMohammadi ◽  
Mohammad Rouhi ◽  
Masoud Rais-Rohani
Keyword(s):  
Topology Optimization ◽  
Volume Fraction ◽  
Structural Response ◽  
Sheet Forming ◽  
Forming Process ◽  
Exchange Method ◽  
Forming Simulation ◽  
Blank Shape Optimization ◽  
Blank Shape ◽  
Consistent Subset

The newly developed element exchange method (EEM) for topology optimization is applied to the problem of blank shape optimization for the sheet-forming process. EEM uses a series of stochastic operations guided by the structural response of the model to switch solid and void elements in a given domain to minimize the objective function while maintaining the specified volume fraction. In application of EEM to blank optimization, a sheet forming simulation model is developed using Abaqus/Explicit. With the goal of minimizing the variability in wall thickness of the formed component, a subset of solid (i.e., high density) elements with the highest increase in thickness is exchanged with a consistent subset of void (i.e., low density) elements having the highest decrease in thickness so that the volume fraction remains constant. The EEM operations coupled with finite element simulations are repeated until the optimum blank geometry (i.e., boundary and initial thickness) is found. The developed numerical framework is applied to blank optimization of a benchmark problem. The results show that EEM is successful in generating the optimum blank geometry efficiently and accurately.

scholarly journals Effect of Differential Speed Rotation Technology on the Forming Uniformity in Flexible Rolling Process

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1906 ◽  
Author(s):  
Yi Li ◽  
Mingzhe Li ◽  
Kai Liu ◽  
Zhuo Li
Keyword(s):  
Element Model ◽  
Rolling Process ◽  
Metal Plate ◽  
Curved Surface ◽  
Forming Process ◽  
Surface Part ◽  
Flexible Rolling ◽  
Speed Rotation ◽  
The One ◽  
Differential Speed

As the local forming non-uniform of the formed curved surface part with larger bending deformation is the one of common defects, the utilization ratio of metal plate greatly reduces due to this defect, and cost of production is also increasing. In this paper, the differential speed rotation technology of flexible rolling process was proposed firstly to solve this forming defect. The finite element model was established, the reason of the local forming non-uniform was discussed; the effect of differential speed rotation technology on the forming uniform was studied. The results show that: Flexible rolling is a process based on thickness reduction, in this forming process, the thickness reduces sharply near the back end of metal plate, the local forming non-uniform of formed curved surface part is caused during this process; the differential speed rotation technology is applied in flexible rolling, with increasing rotation speed difference between upper and lower roll set, the forming uniformity of the formed curved surface part is greatly improved. The results of numerical simulation are in agreement with the result of forming experiments.

Numerical Investigation of Size Effect on Dry Friction Behavior in Micro Upsetting Process

2014 ◽  
Vol 997 ◽  
pp. 321-324
Author(s):  
Wei Zheng ◽  
Guang Chun Wang ◽  
Bing Tao Tang ◽  
Xiao Juan Lin ◽  
Yan Zhi Sun
Keyword(s):  
Friction Coefficient ◽  
Size Effect ◽  
Dry Friction ◽  
Normal Pressure ◽  
Friction Model ◽  
Strain Hardening Exponent ◽  
Forming Process ◽  
Friction Behavior ◽  
Initial Yield Stress ◽  
Coulomb’S Friction

After modifying the Wahime/Bay friction model, a new friction model suitable for micro-forming process without lubrication is established. In this model, it is shows that the friction coefficient is a function of strain hardening exponent, the normal pressure and the initial yield stress of material. Based on the experimental data, the micro-upsetting process is simulated using the proposed friction model. The simulation results are used to investigate the size effect on the dry friction behavior. It is found that the Coulomb’s friction coefficient is dropping with miniaturization of specimens when the amount of reduction is not too large.

BENDING BEHAVIOR OF SIMPLY SUPPOTED METALLIC SANDWICH PLATES WITH DIMPLED CORES

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6179-6184 ◽  
Author(s):  
DAE-YONG SEONG ◽  
CHANG GYUN JUNG ◽  
DONG-YOL YANG ◽  
DONG GYU AHN
Keyword(s):  
High Precision ◽  
Sandwich Plate ◽  
Sheet Thickness ◽  
Radius Of Curvature ◽  
Sandwich Plates ◽  
Collapse Load ◽  
Forming Process ◽  
Simply Supported ◽  
Bending Behavior ◽  
Sandwich Core

Metallic sandwich plates are lightweight structural materials with load-bearing and multi-functional characteristics. Previous analytic studies have shown that the bendability of these plates increases as the thickness decreases. Due to difficulty in the manufacture of thin sandwich plates, dimpled cores (structures called egg-box cores) are employed as a sandwich core. High-precision dimpled cores are easily fabricated in a sectional forming process. The cores are then bonded with skin sheets by multi-point resistance welding. The bending characteristics of simply supported plates were observed by the defining measure, including the radius ratio of the small dimple, the thickness of a sandwich plate, and the pattern angle (0°/90°, 45°). Experimental results revealed that sandwich plates with a thickness of 2.2 mm and a pattern angle of 0°/90° showed good bendability as the punch stroke under a collapse load was longer than other cases. In addition, the gap between attachment points was found to be an important parameter for the improvement of the bendability. Finally, sandwich plates with dimpled cores were bent with a radius of curvature of 330 mm for the sheet thickness of 2.2 mm using an incremental bending apparatus.

scholarly journals Textile composite structural analysis taking into account the forming process

2019 ◽  
Vol 166 ◽  
pp. 773-784 ◽  
Author(s):  
Abderrahmen Aridhi ◽  
Makrem Arfaoui ◽  
Tarek Mabrouki ◽  
Naim Naouar ◽  
Yvan Denis ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Textile Composite ◽  
Forming Process

scholarly journals Draping of Textile Composite Reinforcements: Continuous and Discrete Approaches

2007 ◽  
Vol 16 (4) ◽  
pp. 096369350701600 ◽  
Author(s):  
P. Boisse ◽  
N. Hamila ◽  
F. Helenon ◽  
Y. Aimene ◽  
T. Mabrouki
Keyword(s):  
Finite Elements ◽  
Biaxial Tension ◽  
Textile Composite ◽  
Plane Shear ◽  
Multiscale Materials ◽  
Specific Behaviour ◽  
Unit Cells ◽  
Woven Reinforcement ◽  
Composite Reinforcements

The textile reinforcements used for composites are multiscale materials. A fabric is made of woven yarns themselves composed of thousand of juxtaposed fibres. For the simulation of the draping of these textile reinforcements several families of approaches can be distinguished in function of the level of the modelling. The continuous approaches consider the fabric as a continuum with a specific behaviour. The discrete approaches use models of some components such as the yarns and sometimes the fibres. Different approaches used for the simulation of woven reinforcement forming are investigated in the present paper. Among them, an approach based on semi discrete finite elements made of woven unit cells under biaxial tension and in-plane shear is detailed. The advantage and inconvenient of the different approaches are compared.

scholarly journals Numerical investigation on the forming behaviour of stainless/carbon steel bimetal composite

2018 ◽  
Vol 185 ◽  
pp. 00012
Author(s):  
Zhou Li ◽  
Jingwei Zhao ◽  
Qingfeng Zhang ◽  
Sihai Jiao ◽  
Zhengyi Jiang
Keyword(s):  
Carbon Steel ◽  
Circumferential Stress ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Composite Sheet ◽  
Forming Process ◽  
Thickness Strain ◽  
Forming Simulation ◽  
Bimetal Composite ◽  
Forming Behaviour

Bimetal composites have wide applications due to their excellent overall performance and relatively low comprehensive cost. The aim of this study is to investigate the forming behaviour of stainless/carbon steel bimetal composite during stamping by finite element method (FEM). In this work, the bonding interface of bimetal composite sheet was assumed to be perfect without delamination during the plastic forming process for simplicity. Uniaxial tensile tests on base metal (carbon steel) and compositing metal (stainless steel) were first carried out, respectively, in order to obtain the tensile properties of each of the component materials required in the forming simulation. Processing variables, including the layer stacking sequence, relative thickness ratios of two layers and friction were considered, and their effects on the distributions of circumferential stress and thickness strain were analysed. The bimetal composite sheet was set as the eight-node solid elements in the developed FEM model, which is effective for evaluating the distributions of circumferential stress and thickness strain, and predicting the high-risk region of necking during the stamping of bimetal composites. The simulation results can be used as an evaluation indicator of the capability of forming machine to ensure the bimetal composite can be safely formed.

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