Numerical Modeling of Transient Impact Processes with Large Deformations and Nonlinear Material Behavior

Author(s):  
Ekkehard Ramm ◽  
Tobias Erhart ◽  
Wolfgang A. Wall
2018 ◽  
Vol 3 (1) ◽  
pp. 13-20
Author(s):  
Dávid Huri

Automotive rubber products are subjected to large deformations during working conditions, they often contact with other parts and they show highly nonlinear material behavior. Using finite element software for complex analysis of rubber parts can be a good way, although it has to contain special modules. Different types of rubber materials require the curve fitting possibility and the wide range choice of the material models. It is also important to be able to describe the viscoelastic property and the hysteresis. The remeshing possibility can be a useful tool for large deformation and the working circumstances require the contact and self contact ability as well. This article compares some types of the finite element software available on the market based on the above mentioned features.


2015 ◽  
Vol 813-814 ◽  
pp. 106-110
Author(s):  
Dalbir Singh ◽  
C. Ganesan ◽  
A. Rajaraman

Composites are being used in variety of applications ranging from defense and aircraft structures, where usage is profuse, to vehicle structures and even for repair and rehabilitation. Most of these composites are made of different laminates glued together with matrix for binding and now-a-days fibers of different types are embedded in a composite matrix. The characterizations of material properties of composites are mostly experimental with analytical modeling used to simulate the system behavior. But many times, the composites develop damage or distress in the form of cracking while they are in service and this adds a different dimension as one has to evaluate the response with the damage so that its performance during its remaining life is satisfactory. This is the objective of the present study where a hybrid approach using experimental results on damaged specimens and then analytical finite element are used to evaluate response. This will considerably help in remaining life assessment-RLA- for composites with damage so that design effectiveness with damage could be assessed. This investigation has been carried out on a typical composite with carbon fiber reinforcements, manufactured by IPCL Baroda (India) with trade name INDCARF-30. Experimental studies were conducted on undamaged and damaged specimens to simulate normal continuous loading and discontinuous loading-and-unloading states in actual systems. Based on the experimental results, material characterization inputs are taken and analytical studies were carried out using ANSYS to assess the response under linear and nonlinear material behavior to find the stiffness decay. Using stiffness decay RLA was computed and curves are given to bring the influence of type of damage and load at which damage had occurred.


1977 ◽  
Vol 99 (1) ◽  
pp. 18-23 ◽  
Author(s):  
M. R. Johnson ◽  
R. E. Welch ◽  
K. S. Yeung

A finite-element computer program, which takes into consideration nonlinear material behavior after the yield point has been exceeded, has been used to analyze the thermal stresses in railroad freight car wheels subjected to severe drag brake heating. The analysis has been used with typical wheel material properties and wheel configurations to determine the thermal stress field and the extent of regions in the wheel where the yield point is exceeded. The resulting changes in the residual stress field after the wheel has cooled to ambient temperature have also been calculated. It is shown that severe drag braking can lead to the development of residual circumferential tensile stresses in the rim and radial compressive stresses in the plate near both the hub and rim fillets.


2021 ◽  
Author(s):  
Silvia J. Sarmiento Nova ◽  
Jaime Gonzalez-Libreros ◽  
Gabriel Sas ◽  
Rafael A. Sanabria Díaz ◽  
Maria C. A. Texeira da Silva ◽  
...  

<p>The Response Surface Method (RSM) has become an essential tool to solve structural reliability problems due to its accuracy, efficacy, and facility for coupling with Nonlinear Finite Element Analysis (NLFEA). In this paper, some strategies to improve the RSM efficacy without compromising its accuracy are tested. Initially, each strategy is implemented to assess the safety level of a highly nonlinear explicit limit state function. The strategy with the best results is then identified and used to carry out a reliability analysis of a prestressed concrete bridge, considering the nonlinear material behavior through NLFEA simulation. The calculated value of &#120573; is compared with the target value established in Eurocode for ULS. The results showed how RSM can be a practical methodology and how the improvements presented can reduce the computational cost of a traditional RSM giving a good alternative to simulation methods such as Monte Carlo.</p>


Author(s):  
Eric M. Mockensturm ◽  
Nakhiah Goulbourne

Dielectric elastomers have received a great deal of attention recently for effectively transforming electrical energy to mechanical work. Their large strains and conformability make them enticing materials for many new types of actuators. Unfortunately, their non-linear material behavior and large deformations make actual devices difficult to model. However, the reason for this difficulty can also be used to design actuators that utilize these material and geometric non-linearities to obtain multiple stable equilibria. In this work, we investigate one of the simplest possible configurations, a spherical membrane, using a model that incorporates both mechanical and electrostatic pressure as well as inertial effects that become important when transitioning from one equilibrium to another.


10.29007/r7sp ◽  
2020 ◽  
Author(s):  
Trong Khiem Bui ◽  
Vu Tuong Nguyen ◽  
Thanh Nha Nguyen ◽  
Tich Thien Truong

Hyperelastic materials are special types of material that tends to behavior elastically when they are subjected to very large strains. These materials show not only the nonlinear material behavior but also the large deformation and stress-strain relationship is derived from a strain energy density function. Hyperelastic materials are widely used in many applications such as biological tissues, polymeric foams, and moreover. Neo - Hookean is a material model for hyperelastic solid which contains only two material parameters: bulk modulus and shear modulus. In the field of numerical analysis, the radial point interpolation method (RPIM) is a well-known meshfree method based on Garlekin's weak form. With the property of “free of mesh”, the RPIM approach shows its advantage for large deformation problems. In this study, a meshless radial point interpolation method is applied to demonstrate the elastic response of rubber-like materials based on the Mooney- Rivlin model. The obtained results are compared with the reference solutions given by other methods to verify the accuracy of the proposed method.


Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1582 ◽  
Author(s):  
Varun Sharma ◽  
Fatima Zivic ◽  
Nenad Grujovic ◽  
Norbert Babcsan ◽  
Judith Babcsan

This paper deals with the experimental and numerical study of closed-cell aluminum-based foam under compressive loading. Experimental samples were produced by the gas blowing method. Foam samples had an average cell size of around 1 mm, with sizes in the range 0.5–5 mm, and foam density of 0.6 g/cm3. Foam samples were subjected to a uniaxial compression test, at a displacement rate of 0.001 mm/s. Load and stress were monitored as the functions of extension and strain, respectively. For numerical modeling, CT scan images of experimental samples were used to create a volume model. Solid 3D quadratic tetrahedron mesh with TETRA 10-node elements was applied, with isotropic material behavior. A nonlinear static test with an elasto-plastic model was used in the numerical simulation, with von Mises criteria, and strain was kept below 10% by the software. Uniform compressive loading was set up over the top sample surface, in the y-axis direction only. Experimental tests showed that a 90 kN load produced complete failure of the sample, and three zones were exhibited: an elastic region, a rather uniform plateau region (around 23 MPa) and a densification region that started around 35 MPa. Yielding, or collapse stress, was achieved around 20 MPa. The densification region and a rapid rise in stress began at around 52% of sample deformation. The numerical model showed both compressive and tensile stresses within the complex stress field, indicating that shear also had a prominent role. Mainly compressive stresses were exhibited in the zones of the larger cells, whereas tensile stresses occurred in zones with an increased number of small cells and thin cell walls.


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