Numerical Simulation of Different Clamping Modes on Stretch Forming Parts

2011 ◽  
Vol 189-193 ◽  
pp. 1922-1925 ◽  
Author(s):  
Xue Chen ◽  
Mine Zhe Li ◽  
Wen Zhi Fu ◽  
Zhong Yi Cai

Three clamping devices of stretch forming machine were introduced, and the corresponding finite element models of the spherical parts were built by finite element software, the strain and thickness distribution of the forming parts were comparatively analyzed. The simulation results show that strain and thickness distribution of the forming parts with the multiple discrete gripper clamping mode are well-proportioned, its forming quality gets better than that with the whole flat gripper and adjustable curved gripper clamping modes. The experiment was performed and a typical spherical parts was formed with the multiple discrete gripper clamping mode. The experimental results are in good agreement with simulation results, which proves feasibility and practicability of the multiple discrete gripper clamping device of stretch forming machine.

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 337 ◽  
Author(s):  
Jian Xing ◽  
Yan-yan Cheng ◽  
Zhuo Yi

To improve the effect of multi-point stretch forming of sheet metal, it is proposed in this paper to replace a fixed ball head with a swinging ball head. According to the multi-point dies with different arrangements, this research establishes finite element models of the following stretch forming, i.e., fixed ball heads with conventional arrangement, swinging ball heads with conventional arrangement, swinging ball heads with declining staggered arrangement, and swinging ball heads with parallel staggered arrangement, and then numerical simulation is performed. The simulation results show that by replacing a fixed ball head with a swinging ball head, the surface indentation of the part formed was effectively suppressed, the stress and tension strain distribution of the part formed was improved, and the forming quality was improved; the thickness of the elastic pad was reduced, the springback was reduced and the forming accuracy was improved; and when the ball head was applied to a multi-point die with staggered arrangement, a better forming result was achieved, where the best forming result was achieved in combining the swinging ball heads with the multi-point die with a parallel staggered arrangement. Forming experiments were carried out, and the experimental results were consistent with the trend of numerical simulation results, which verified the correctness of the numerical simulation.


Author(s):  
Jian Xing ◽  
Yan-yan Cheng ◽  
Zhuo Yi

To improve the effect of multi-point stretch forming of sheet metal, it is proposed in this paper to replace fixed ball head with swinging ball head. According to the multi-point dies with different arrangements, this research establishes the finite element models of the following stretch forming, i.e. fixed ball heads with conventional arrangement, swinging ball heads with conventional arrangement, swinging ball heads with declining staggered arrangement, and swinging ball heads with parallel staggered arrangement and then numerical simulation is performed. The simulation results show that by replacing fixed ball head with swinging ball head, the surface indentation of the formed part was effectively suppressed, the stress and tension strain distribution of the formed part was improved and the forming quality was improved; that the thickness of the elastic pad was reduced, the springback was reduced and the forming accuracy was improved; and that when the ball head was applied to multi-point die with staggered arrangement, better forming result was achieved, where the best forming result was achieved in combining the swinging ball heads with the multi-point die with parallel staggered arrangement. The forming experiments were carried out, and the experimental results were consistent with the trend of numerical simulation results, which verified the correctness of the numerical simulation.


2016 ◽  
Vol 16 (07) ◽  
pp. 1550035 ◽  
Author(s):  
Chen-Cheng Chung ◽  
Kuo-Long Lee ◽  
Wen-Fung Pan

The mechanical behavior and buckling failure of sharp-notched 6061-T6 aluminum alloy tubes with different notch depths subjected to cyclic bending are experimentally and theoretically investigated. The experimental moment–curvature relationship exhibits an almost steady loop from the beginning of the first cycle. However, the ovalization–curvature relationship exhibits a symmetrical, increasing, and ratcheting behavior as the number of cycles increases. The six groups of tubes tested have different notch depths, from which two different trends can be observed from the relationship between the controlled curvature and the number of cycles required to ignite buckling. Finite element software ANSYS is used to simulate the moment–curvature and ovalization–curvature relationships. Additionally, a theoretical model is proposed for simulation of the controlled curvature-number of cycles concerning the initiation of buckling. Simulation results are compared with experimental test data, which shows generally good agreement.


2014 ◽  
Vol 626 ◽  
pp. 334-339
Author(s):  
Te Fu Huang ◽  
Hsin Yi Hsien ◽  
Yan Jia Chen

The friction holding effect and the friction reducing effect occurring during Hydraulic Deep Drawing and the pre-bulging resulting in more plastic deformation on products are applied on sheet hydro-forming. For Hydraulic Deep Drawing of a square cup, the thickness distribution and the relation between the height and the pressure of pre-bulging are simulated with SPCC steels as the specimen by the finite element method. An experimental apparatus of sheet hydro-forming has been constructed to carry out the hydraulic deep drawing experiments of square cups. Experimental thickness distribution and punch load are compared with simulation results. Good agreement was found. The flow patterns of the circular and square blanks with the condition of being firmly pressed against the punch observed from the experiments are in agreement with the predicted results.Keywords:Hydraulic Deep Drawing, sheet hydro-forming, finite element method


2012 ◽  
Vol 630 ◽  
pp. 121-126
Author(s):  
Gong Wu Huang ◽  
Ai Jun Chen ◽  
Shao Min Luo ◽  
Cheng Xu

Finite element models of bullet penetrating UHMWPE fiber layers are established to study the relationship between parameters of projectile and penetration ability using LS-DYNA software. The numerical simulation results of penetration calculated in Lagrange algorithm are in good agreement with the real experimental results, which verify the validity of the finite element models and algorithm. The numerical results show that high speed and small angle of attack can improve the penetration ability, the penetration ability of oval projectile is better than flat head projectile. A valid and reliable research approach for evaluating the design of protective equipment and efficiency of projectiles are proposed.


2019 ◽  
Vol 947 ◽  
pp. 125-129
Author(s):  
Y.C. Liu ◽  
Y.C. Huang ◽  
Yun Jhe Tang ◽  
Tzu Hsuan Lei

This article presents a finite element simulation method for airflow resistance of material to predict the influence of absorption material applied to compressor box. To obtain the real airflow resistance, a measurement system based on the standard ASTM C522-03 was systematically built up and carefully verified. Furthermore, commercial finite element software, COMSOL Multiphysics, was adopted to create the model and execute the simulation with and without absorption material. Results showed that airflow resistance increases with the thickness and the density of the material. This system is quite stable and suited to any material. With the aid of COMSOL Multiphysics simulations, the performance of noise with and without absorption material can be analyzed and compared with experimental results. There was good agreement between experimental and simulation results. Based on absorption material of 15,278 Pa.s/m3 airflow resistance, the noise level outside the compressor box obtained from experiment was around 10 dBA higher than that obtained from simulation.


Author(s):  
Haolei Mou ◽  
Zhenyu Feng ◽  
Jiang Xie ◽  
Jun Zou ◽  
Kun Zhou

AbstractTo analysis the failure and energy absorption of carbon fiber reinforced polymer (CFRP) thin-walled square tube, the quasi-static axial compression loading tests are conducted for [±45]3s square tube, and the square tube after test is scanned to further investigate the failure mechanism. Three different finite element models, i.e. single-layer shell model, multi-layer shell model and stacked shell mode, are developed by using the Puck 2000 matrix failure criterion and Yamada Sun fiber failure criterion, and three models are verified and compared according to the experimental energy absorption metrics. The experimental and simulation results show that the failure mode of [±45]3s square tube is the local buckling failure mode, and the energy are absorbed mainly by intralaminar and interlaminar delamination, fiber elastic deformation, fiber debonding and fracture, matrix deformation cracking and longitudinal crack propagation. Three different finite element models can reproduce the collapse behaviours of [±45]3s square tube to some extent, but the stacked shell model can better reproduce the failure mode, and the difference of specific energy absorption (SEA) is minimum, which shows the numerical simulation results are in better agreement with the test results.


2014 ◽  
Vol 511-512 ◽  
pp. 561-564
Author(s):  
Ji Bo Li ◽  
Wei Ning Ni ◽  
San Guo Li ◽  
Zu Yang Zhu

Pressure resistant performance of Measure While Drilling (MWD) microchip tracer to withstand the harsh downhole environment is one of the key issues of normal working. Therefore, it is an effective way to analyze pressure resistant performance of the tracer in the design phase. Compressive strength of the tracer was studied based on finite element method. Considering downhole complexity and working conditions during the processing of tracer roundness, material non-uniformity and other factors. In this study, researchers took sub-proportion failure criterion to determine the failure of tracer. Simulation results of two structures, with pin and without pin, show that both structures met the requirement of downhole compressive strength, and the structure with pin was better than the structure without pin. This study provides basis for downhole application of microchip tracers.


2013 ◽  
Vol 813 ◽  
pp. 355-358 ◽  
Author(s):  
Ting Ting Wang ◽  
Wan Chun Zhao ◽  
Yuan Hong Liu ◽  
Li Yang ◽  
Hong Yu Gao

In order to accurately describe the growth behavior of the micro-fracture under the action of the rock external load, this paper proposes the use of chaos theory to describe the fracture formation process, explains the chaotic characteristics of the fracture from the perspective of the growth of micro-fracture, the number of growth and fracture formation morphology, respectively. Selecting the practical block of an oilfield, the theoretical calculation and finite element software simulation results show that, theoretical calculations are accurate and reliable.


Author(s):  
Lý Hùng Anh ◽  
Nguyễn Phụ Thượng Lưu ◽  
Nguyễn Thiên Phú ◽  
Trần Đình Nhật

The experimental method used in a frontal crash of cars costs much time and expense. Therefore, numerical simulation in crashworthiness is widely applied in the world. The completed car models contain a lot of parts which provided complicated structure, especially the rear of car models do not contribute to behavior of frontal crash which usually evaluates injuries of pedestrian or motorcyclist. In order to save time and resources, a simplification of the car models for research simulations is essential with the goal of reducing approximately 50% of car model elements and nodes. This study aims to construct the finite element models of front structures of vehicle based on the original finite element models. Those new car models must be maintained important values such as mass and center of gravity position. By using condition boundaries, inertia moment is kept unchanged on new model. The original car models, which are provided by the National Crash Analysis Center (NCAC), validated by using results from experimental crash tests. The modified (simplistic) vehicle FE models are validated by comparing simulation results with experimental data and simulation results of the original vehicle finite element models. LS-Dyna software provides convenient tools and very strong to modify finite element model. There are six car models reconstructed in this research, including 1 Pick-up, 2 SUV and 3 Sedan. Because car models were not the main object to evaluate in a crash, energy and behavior of frontal part have the most important role. As a result, six simplified car models gave reasonable outcomes and reduced significantly the number of nodes and elements. Therefore, the simulation time is also reduced a lot. Simplified car models can be applied to the upcoming frontal simulations.


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