Investigation on V-Bending and Springback of Laminated Steel Sheets

Author(s):  
Qiongyao Peng ◽  
Xiongqi Peng ◽  
Yinjun Wang ◽  
Tao Wang

Laminated steel sheet (LSS) is a novel functional material consisting of two steel sheets sandwiched by an adhesive layer. It has good vibration damping and noise absorption attributed by the middle polymer layer, and structural function owed to the two face steel sheets. Springback is an omnipresent negative phenomenon in metal sheet bending. Experiments and simulations were conducted to analyze the effects of processing and material parameters on springback of a specified LSS for the purpose of process optimization. Various tests including lap-shear, normal tensile, and viscosity analysis were carried out to obtain the mechanical behavior of the polymer layer. A neo-Hookean hyperelastic model was accordingly developed. Tensile tests of the two skin sheets were also implemented for material model. Ninety degree V-bending experiments were fulfilled as a validation on the feasibility and efficiency of finite element method and material models. A following parametric study on 88 deg V-bending of the LSS was then implemented to provide a processing optimization for industry practice.

2014 ◽  
Vol 939 ◽  
pp. 328-335 ◽  
Author(s):  
V. Satheeshkumar ◽  
R. Ganesh Narayanan

In the present investigation, the forming behaviour of adhesive bonded sheets with the pre-generated infinite defects in the adhesive layer is studied. The infinite defects are generated with different orientations like longitudinal, transverse and at an angle of 45°. The base sheet materials used are deep drawing quality steel and SS 316L sheets, and two part epoxy adhesive is used for bonding the base sheet materials. The formability is quantified by monitoring the load-extension behaviour, and limit strain, evaluated through tensile tests and in-plane plane strain (IPPS) formability tests. It is observed that there is a significant decrease in formability because of the presence of infinite defects in the adhesive layer. While comparing the formability of adhesive bonded blanks with respect to different orientations, transversely oriented defect shows more reduction than 45° and longitudinal cases. There is not much difference between the transversely oriented and 45° oriented infinite defects in tensile tests, whereas in the IPPS formability test results, there is no considerable difference between 45° and longitudinally oriented defect.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1553
Author(s):  
Mária Mihaliková ◽  
Kristína Zgodavová ◽  
Peter Bober ◽  
Anna Špegárová

The presented research background is a car body manufacturer’s request to test the car body’s components welded from dissimilar steel sheets. In view of the vehicle crew’s protection, it is necessary to study the static and dynamic behavior of welded steels. Therefore, the influence of laser welding on the mechanical and dynamical properties, microstructure, microhardness, and welded joint surface roughness of interstitial free CR180IF and dual-phase DP600 steels were investigated. Static tensile tests were carried out by using testing machine Zwick 1387, and dynamic test used rotary hammer machine RSO. Sheet steel was tested at different strain rates ranging from 10−3 to 103 s−1. The laser welds’ microstructure and microhardness were evaluated in the base metal, heat-affected zone, and fusion zone. The comprehensive analysis also included chemical analysis, fracture surface analysis, and roughness measurement. The research results showed that the strain rate had an influence on the mechanical properties of base materials and welded joints. The dynamic loading increases the yield stress more than the ultimate tensile strength for the monitored steels, while the most significant increase was recorded for the welded material.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4585
Author(s):  
Marian Bulla ◽  
Stefan Kolling ◽  
Elham Sahraei

The present study is focused on the development of a material model where the orthotropic-visco-elastic and orthotropic-visco-plastic mechanical behavior of a polymeric material is considered. The increasing need to reduce the climate-damaging exhaust gases in the automotive industry leads to an increasing usage of electric powered drive systems using Lithium-ion (Li-ion) batteries. For the safety and crashworthiness investigations, a deeper understanding of the mechanical behavior under high and dynamic loads is needed. In order to prevent internal short circuits and thermal runaways within a Li-ion battery, the separator plays a crucial role. Based on results of material tests, a novel material model for finite element analysis (FEA) is developed using the explicit solver Altair Radioss. Based on this model, the visco-elastic-orthotropic, as well as the visco-plastic-orthotropic, behavior until failure can be modeled. Finally, a FE simulation model of the separator material is performed, using the results of different tensile tests conducted at three different velocities, 0.1 mm·s−1, 1.0 mm·s−1 and 10.0 mm·s−1 and different orientations of the specimen. The purpose is to predict the anisotropic, rate-dependent stiffness behavior of separator materials in order to improve FE simulations of the mechanical behavior of batteries and therefore reduce the development time of electrically powered vehicles and consumer goods. The present novel material model in combination with a well-suited failure criterion, which considers the different states of stress and anisotropic-visco-dependent failure limits, can be applied for crashworthiness FE analysis. The model succeeded in predicting anisotropic, visco-elastic orthotropic and visco-plastic orthotropic stiffness behavior up to failure.


2012 ◽  
Vol 217-219 ◽  
pp. 1497-1500 ◽  
Author(s):  
Xiao Jun Zuo ◽  
Jun Chu Li ◽  
Da Hai Liu ◽  
Long Fei Zeng

Constructing accurate constitutive equation from the optimal material constants is the basis for finite element numerical simulation. To accurately describe the creep ageing behavior of 2A12 aluminum alloy, the present work is tentatively to construct an elastic-plastic constitutive model for simulation based on the ANSYS environment. A time hardening model including two stages of primary and steady-state is physically derived firstly, and then determined by electronic creep tensile tests. The material constants within the creep constitutive equations are obtained. Furthermore, to verify the feasibility of the material model, the ANSYS based numerical scheme is established to simulate the creep tensile process by using the proposed material model. Results show that the creep constitutive equation can better describe the deformation characteristics of materials, and the numerical simulations and experimental test points are in good agreement.


Author(s):  
Jan M. Kubiczek ◽  
Boyuan Liang ◽  
Lars Molter ◽  
Sören Ehlers

Collisions and grounding accidents of ships, but also the failure of the hull-integrity, can lead to oil leakage. Examples are the Rena in 2011, the Hebei Spirit in 2007 and the much known accident of the Prestige in 2002. Consequently research regarding the enhancement of the structural design to increase the safety-level of ships in case of accidents is important. In this paper the use of a rubber bag as a second barrier is presented as an alternative concept to prevent oil leakage in case of accidents. The influence of the rubber bag is investigated using the example of a ship collision. A simplified tanker side structure as well as a box shaped rubber bag are analyzed with the finite element method. The material model for the rubber bag is calibrated with tensile tests to obtain the required material parameters. The reaction forces and the associated penetration depth are analyzed. The comparison is done between the structure with and without the rubber bag. For the latter, the general behavior is compared with large-scale experimental results. Furthermore an additional increase of the survivability of the ship due to the rubber bag without changing the common structural design is discussed.


Author(s):  
Varatharajan Prasannavenkadesan ◽  
Ponnusamy Pandithevan

Abstract In orthopedic surgery, bone cutting is an indispensable procedure followed by the surgeons to treat the fractured and fragmented bones. Because of the unsuitable parameter values used in the cutting processes, micro crack, fragmentation, and thermal osteonecrosis of bone are observed. Therefore, prediction of suitable cutting force is essential to subtract the bone without any adverse effect. In this study, the Cowper-Symonds model for bovine bone was developed for the first time. Then the developed model was coupled with the finite element analysis to predict the cutting force. To determine the model constants, tensile tests with different strain rates (10−5/s, 10−4/s, 10−3/s, and 1/s) were conducted on the cortical bone specimens. The developed material model was implemented in the bone cutting simulation and validated with the experiments.


Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1391
Author(s):  
Lanxin Jiang ◽  
Bing Yang ◽  
Shoune Xiao ◽  
Guangwu Yang ◽  
Tao Zhu ◽  
...  

In order to study the interfacial adhesive material simulation method of a sandwich structure with aluminum alloy panels and a low-density foam core under edgewise compression condition, two finite element models were defined using material model no. 185 (MAT 185) adhesive element and tiebreak contact, respectively, by LS-DYNA. Under the conditions of different loading rates, and element sizes, the effects of peak load, energy absorption, failure mode of adhesive layer and the influence degree of the changing condition on the calculated results were compared between the two models, and then compared with the experiment results and theoretical results. The higher the loading rate was, or the smaller the element size was, the higher the peak load was. The simulation results obtained using MAT 185 were closer to the experimental results under the edgewise compression condition.


Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2241 ◽  
Author(s):  
Tomáš Hána ◽  
Tomáš Janda ◽  
Jaroslav Schmidt ◽  
Alena Zemanová ◽  
Michal Šejnoha ◽  
...  

An accurate material representation of polymeric interlayers in laminated glass panes has proved fundamental for a reliable prediction of their response in both static and dynamic loading regimes. This issue is addressed in the present contribution by examining the time–temperature sensitivity of the shear stiffness of two widely used interlayers made of polyvinyl butyral (TROSIFOL BG R20) and ethylene-vinyl acetate (EVALAM 80-120). To that end, an experimental program has been executed to compare the applicability of two experimental techniques, (i) dynamic torsional tests and (ii) dynamic single-lap shear tests, in providing data needed in a subsequent calibration of a suitable material model. Herein, attention is limited to the identification of material parameters of the generalized Maxwell chain model through the combination of linear regression and the Nelder–Mead method. The choice of the viscoelastic material model has also been supported experimentally. The resulting model parameters confirmed a strong material variability of both interlayers with temperature and time. While higher initial shear stiffness was observed for the polyvinyl butyral interlayer in general, the ethylene-vinyl acetate interlayer exhibited a less pronounced decay of stiffness over time and a stiffer response in long-term loading.


Author(s):  
Lidong Wang ◽  
Xiongqi Peng ◽  
Mingrui Liu

The basic mechanical properties of a diaphragm under various temperatures in hot diaphragm preforming of composites are obtained by uniaxial tensile tests. A constitutive model considering the influence of temperature is accordingly developed to characterize its large deformation behavior. Model parameters are obtained by nonlinear fitting experiment data. The constitutive model is implemented in ABAQUS through the user material subroutine UHYPER. The developed constitutive model is verified by simulating the covering deformation of the diaphragm over a C-type mold. Finally, as an application of the developed hyperelastic model, an optimal design of a support bar in the hot diaphragm preforming process is implemented. The constitutive model lays a solid foundation for the finite element simulation and process optimization of the hot diaphragm forming (HDF) of carbon composites.


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