scholarly journals Numerical and Experimental Results on Charpy Tests for Blends Polypropylene + Polyamide + Ethylene Propylene Diene Monomer (PP + PA + EPDM)

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5837
Author(s):  
Cătălin Pîrvu ◽  
Andreea Elena Musteată ◽  
George Ghiocel Ojoc ◽  
Lorena Deleanu
Keyword(s):  
Equivalent Plastic Strain ◽  
Material Model ◽  
Element Model ◽  
Tensile Tests ◽  
Experimental Results ◽  
Low Velocity ◽  
Sem Images ◽  
Charpy Test ◽  
Simulation Results ◽  
The Impact

This paper presents results from numerical and experimental investigation on Charpy tests in order to point out failure mechanisms and to evaluate new polymeric blends PP + PA6 + EPDM. Charpy tests were done for initial velocity of the impactor of 0.96 m/s and its mass of 3.219 kg and these data were also introduced in the finite element model. The proposed model takes into account the system of four balls, including support and the ring of fixing the three balls and it has a finer discretization of the impact area to highlight the mechanisms of failure and their development in time. The constitutive models for four materials (polypropylene with 1% Kritilen, two blends PP + PA6 + EPDM and a blend PA6 + EPDM) were derived from tensile tests. Running simulations for each constitutive model of material makes possible to differentiate the destruction mechanisms according to the material introduced in the simulation, including the initiation and the development of the crack(s), based on equivalent plastic strain at break (EPS) for each material. The validation of the model and the simulation results were done qualitatively, analyzing the shape of broken surfaces and comparing them to SEM images and quantitatively by comparing the impact duration, energy absorbed by the sample, the value of maximum force during impact. The duration of the destruction of the specimen is longer than the actual one, explainable by the fact that the material model does not take into account the influence of the material deformation speed in Charpy test, the model being designed with the help of tests done at 0.016 m/s (1000 mm/min) (maximum strain rate for the tensile tests). Experimental results are encouraging for recommending the blends 20% PP + 42% PA6 + 28% EPDM and 60% PA6 + 40% EPDM as materials for impact protection at low velocity (1 m/s). Simulation results are closer to the experimental ones for the more brittle tested materials (with less content of PA6 and EPDM) and more distanced for the more ductile materials (with higher content of PA6 and EPDM).

scholarly journals Numerical and Experimental Results on Charpy Tests for Blends Polypropylene + Polyamide + Ethylene Propylene Diene Monomer (PP+PA+EDPM)

2020 ◽  
Author(s):  
Catalin Pirvu ◽  
Andreea Elena Musteata ◽  
George Ghiocel Ojoc ◽  
Lorena Deleanu
Keyword(s):  
Equivalent Plastic Strain ◽  
Material Model ◽  
Element Model ◽  
Tensile Tests ◽  
Experimental Results ◽  
Low Velocity ◽  
Sem Images ◽  
Charpy Test ◽  
Simulation Results ◽  
The Impact

This paper presents results from numerical and experimental investigation on Charpy tests in order to point out failure mechanisms and to evaluate new polymeric blends PP+PA6+EPDM. Charpy tests were done for initial velocity of the impactor of 0.96 m/s and its mass of 3.219 kg and these data were also introduced in the finite element model. The proposed model take into account the system of four balls, including support and the ring of fixing the three balls and it has a finer discretization of the impact area to highlight the mechanisms of failure and their development in time. The constitutive models for four materials (polypropylene with 1% Kritilen, two blends PP+PA6+EPDM and a blend PA6+EPDM) were derived from tensile tests. Running simulations for each constitutive model of material makes possible to differentiate the destruction mechanisms according to the material introduced in the simulation, including the initiation and the development of the crack(s), based on equivalent plastic strain at break (EPS) for each material. The validation of the model and the simulation results was done qualitatively, analysing the shape of broken surfaces and comparing them to SEM images and quantitatively by comparing the impact duration, energy absorbed by the sample, the value of maximum force during impact. The duration of the destruction of the specimen is longer than the actual one, explainable by the fact that the material model does not take into account the influence of the material deformation speed in Charpy test, the model being designed with the help of tests done at 0.016 m/s (1000 mm/min) (maximum strain rate for the tensile tests). Experimental results are encouraging for recommending the blends 20% PP+42% PA6+28% EPDM and 60% PA6+ 40%EPDM as materials for impact protection at low velocity (1m/s). Simulation results are closer to the experimental ones for the more brittle tested materials (with less content of PA6 and EPDM) and more distanced for the more ductile materials (with higher content of PA6 and EPDM).

Numerical Simulation of Multi-Angle Incidence Aluminum Composite Targets with 7.62mm Piercing Armor

2014 ◽  
Vol 602-605 ◽  
pp. 562-565
Author(s):  
Yu Lei Li ◽  
Jin Jun Tang ◽  
Xiao Yu Jin ◽  
Qun Wang ◽  
Zheng Ren
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Material Model ◽  
Element Model ◽  
Target Plate ◽  
Aluminum Composite ◽  
3D Finite Element ◽  
Aluminum Target ◽  
Simulation Results ◽  
The Impact

To calculate the multi-angle penetration, this paper established a 3D finite element model of aluminum alloy plates and 7.62mm armor-piercing by using LS-DYNA software and the Johnson-Cook material model. The process of bullet penetrating 20mm thickness target with different angles of incidence was carried out. The impact of combinations on composite targets resistance projectile penetrating ability was analyzed. Simulation results show that,ballistic of composite targets can be between two aluminum target plate, clearly different combinations of composite targets for resistance to different angles of incidence between projectile penetrating relationship.

scholarly journals Investigation of the Thickness Differential on the Formability of Aluminum Tailor Welded Blanks

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 875
Author(s):  
Jie Wu ◽  
Yuri Hovanski ◽  
Michael Miles
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Numerical Model ◽  
Plastic Strain ◽  
Finite Element Model ◽  
Equivalent Plastic Strain ◽  
Element Model ◽  
Dome Height ◽  
Tailor Welded Blanks ◽  
Simulation Results

A finite element model is proposed to investigate the effect of thickness differential on Limiting Dome Height (LDH) testing of aluminum tailor-welded blanks. The numerical model is validated via comparison of the equivalent plastic strain and displacement distribution between the simulation results and the experimental data. The normalized equivalent plastic strain and normalized LDH values are proposed as a means of quantifying the influence of thickness differential for a variety of different ratios. Increasing thickness differential was found to decrease the normalized equivalent plastic strain and normalized LDH values, this providing an evaluation of blank formability.

scholarly journals Numerical–Experimental Correlation of Impact-Induced Damages in CFRP Laminates

2019 ◽  
Vol 9 (11) ◽  
pp. 2372 ◽  
Author(s):  
Andrea Sellitto ◽  
Salvatore Saputo ◽  
Francesco Di Caprio ◽  
Aniello Riccio ◽  
Angela Russo ◽  
...  
Keyword(s):  
Numerical Model ◽  
Composite Laminates ◽  
Transverse Direction ◽  
Material Model ◽  
Low Velocity ◽  
Cfrp Laminates ◽  
Experimental Correlation ◽  
Out Of Plane ◽  
Impact Phenomena ◽  
The Impact

Composite laminates are characterized by high mechanical in-plane properties and poor out-of-plane characteristics. This issue becomes even more relevant when dealing with impact phenomena occurring in the transverse direction. In aeronautics, Low Velocity Impacts (LVIs) may occur during the service life of the aircraft. LVI may produce damage inside the laminate, which are not easily detectable and can seriously degrade the mechanical properties of the structure. In this paper, a numerical-experimental investigation is carried out, in order to study the mechanical behavior of rectangular laminated specimens subjected to low velocity impacts. The numerical model that best represents the impact phenomenon has been chosen by numerical–analytical investigations. A user defined material model (VUMAT) has been developed in Abaqus/Explicit environment to simulate the composite intra-laminar damage behavior in solid elements. The analyses results were compared to experimental test data on a laminated specimen, performed according to ASTM D7136 standard, in order to verify the robustness of the adopted numerical model and the influence of modeling parameters on the accuracy of numerical results.

scholarly journals Small Caliber Bulletproof Test of Warships’ Hulls

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3848
Author(s):  
Radosław Kiciński ◽  
Andrzej Kubit
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Method Simulation ◽  
Material Model ◽  
Experimental Results ◽  
Material Constants ◽  
Steel Core ◽  
Calculation Results ◽  
Simulation Results

The article presents the characteristics of 1.3964 steel and the results of firing a 7.62 mm projectile with a steel core. A simplified Johnson–Cook material model for steel and projectile was used. Then, a FEM (finite element method) simulation was prepared to calibrate the material constants and boundary conditions necessary to be used in simulations of the entire hull model. It was checked how projectile modeling affects the FEM calculation results. After obtaining the simulation results consistent with the experimental results, using the model of a modern minehunter, the resistance of the ship’s hull to penetration by a small-caliber projectile was tested.

FE Modeling of the Three-Layer Human Carotid Artery Under Impact Loadings

2007 ◽  
Author(s):  
Aihong Zhao ◽  
Ken Digges ◽  
Mark Field ◽  
David Richens
Keyword(s):  
Finite Element ◽  
Carotid Artery ◽  
Model Simulation ◽  
Material Model ◽  
Element Model ◽  
Traumatic Rupture ◽  
Aortic Tissue ◽  
Fe Model ◽  
Arbitrary Lagrangian Eulerian ◽  
The Impact

Blunt traumatic rupture of the carotid artery is a rare but life threatening injury. The histology of the artery is key to understanding the aetiology of this injury. The carotid artery is composed of three layers known as the tunica intima, media, and adventitia, with distinct biomechanical properties. In order to examine the behaviour of the carotid artery under external load we have developed a three layer finite element model of this vessel. A rubber-like material model from LS-DYNA was selected for the FE model. The Arbitrary-Lagrangian Eulerian (ALE) approach was adopted to simulate the interaction between the fluid (blood) and the structure (carotid). To verify the FE model, the impact bending tests are simulated using this FE model. Simulation results agree with tests results well. Furthermore, the mechanical behaviour of carotid artery tissues under impact loading were revealed by the simulations. The results provide a basis for a more in-depth investigation of the carotid artery in vehicle crashes. In addition, it provides a basis for further work on aortic tissue finite element modeling.

scholarly journals Influence of hydrogen on mechanical properties of pure titanium T40 (grade 2) and TA6V ELI (grade 23): a local approach of fracture

2020 ◽  
Vol 321 ◽  
pp. 09004
Author(s):  
Alexandre POLONI ◽  
Abdelali OUDRISS ◽  
Juan CREUS ◽  
Stéphane COHENDOZ ◽  
Jamaa Bouhattate ◽  
...  
Keyword(s):  
Cathodic Polarization ◽  
Hydrostatic Stress ◽  
Equivalent Plastic Strain ◽  
Pure Titanium ◽  
Tensile Tests ◽  
Solubility Limit ◽  
Local Approach ◽  
Hydrogen Charging ◽  
Β Phase ◽  
The Impact

The effect of hydrogen charging by cathodic polarization on T40 (grade 2) and TA6V ELI (grade 23) in artificial seawater appeared to be dependent on the metallurgical structure of the alloys. Mechanical tensile tests were performed on smooth samples and with different notches without and with hydrogen charging. Evolution of the fracture mode has been studied and the impact of hydrides was questioned. FEM calculation offers the opportunity to associate the local hydrostatic stress σm and equivalent plastic strain εpeq leading to the fracture and to illustrate the evolution of these conditions with hydrogen absorption and hydrides formation. Hydrogen charged by cathodic polarization appeared to have a small impact on grade 2 reducing its A%, whereas it leads to a strong embrittlement of grade 23 when the solubility limit of β-phase is exceeded and hydrides formed.

scholarly journals Material Characterization for FEM Simulation of Sheet Metal Stamping Processes

2014 ◽  
Vol 6 ◽  
pp. 167147 ◽  
Author(s):  
Alejandro Quesada ◽  
Antonio Gauchia ◽  
Carolina Álvarez-Caldas ◽  
José Luis San Román
Keyword(s):  
Sheet Metal ◽  
Manufacturing Industry ◽  
Fem Simulation ◽  
Main Tool ◽  
Material Model ◽  
Experimental Results ◽  
Simulation Tools ◽  
Sheet Metal Parts ◽  
Simulation Results ◽  
Parameter Values

Sheet metal forming is an important technology in manufacturing, especially in the automotive industry. Today, engineering simulation tools based on the finite elements method are employed regularly in the design of stamping dies for sheet metal parts. However, a bad material model choice or the use of nonaccurate enough parameters can lead to imprecise simulation results. This work uses ANSYS LS-DYNA software to analyze several material models and the influence of their parameter values in FEM simulation results. The main tool to solve these problems is an application designed to assist die stamp designers. The program allows a procedure to be defined to obtain the values of the properties of an unknown material, which combines finite element simulations with real experimental results. Results obtained for the simulation of a real automotive part are analyzed and compared with the real experimental results. Parameters involved in each material model have been identified, and their influence in final results has been quantified. This is very useful to fit material properties in other simulations. This paper fulfils an identified need in the manufacturing industry. In fact, the proposed application is currently being used by a manufacturer of automotive components.

Numerical Analysis of Superplastic Bulging Process of TiAl Sheet

2013 ◽  
Vol 747-748 ◽  
pp. 50-56
Author(s):  
Chuan Yun Wang ◽  
Jin Shan Li ◽  
Bin Tang ◽  
Hong Chao Kou
Keyword(s):  
Present Model ◽  
Thickness Distribution ◽  
Equivalent Plastic Strain ◽  
Element Model ◽  
Dominant Factor ◽  
Tial Alloys ◽  
Deformation Parameters ◽  
Nonuniform Thickness ◽  
Simulation Results ◽  
Good Agreement

The superplastic bulging process of TiAl sheet was simulated by coupling superplastic constitutive equation to finite element model. Based on this model, the effect of coefficient of friction between the sheet and mold and the size of the mold fillet on the superplastic bulging (SPB) performance of TiAl alloys sheet were studied by analyzing the evolution of equivalent plastic strain and thickness distribution in the sheet. The results showed that friction was the dominant factor of the nonuniform thickness of the sheet, while higher friction and smaller radius of mold fillet inhibited the over-thinning of sheet on the entry of mold cavity. The simulation results were in good agreement with the experimental results. Therefore, the present model could be used for optimizing the selction of the deformation parameters and the design of the structures.

scholarly journals Nonlinear Material Model for Quasi-Unidirectional Woven Composite Accounting for Viscoelastic, Viscous Deformation, and Stiffness Reduction

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 903 ◽  
Author(s):  
Zhanyu Zhai ◽  
Bingyan Jiang ◽  
Dietmar Drummer
Keyword(s):  
Material Model ◽  
Tensile Tests ◽  
Experimental Results ◽  
Nonlinear Material ◽  
Weibull Function ◽  
Viscous Deformation ◽  
Stiffness Reduction ◽  
Viscoelastic Strain ◽  
Proposed Model ◽  
The Individual

To clarify the individual contribution of viscoelastic and viscous deformation to the global nonlinear response of composites, multilevel cyclic loading-unloading recovery tensile tests were carried out. The experimental results show that there is a linear relationship between the viscous strain and viscoelastic strain of composites, regardless of the off-axis angle or loading stress level. On the basis of experimental results, a coupled damage-plasticity constitutive model was proposed. In this model, the plasticity theory was adopted to assess the evolution of viscous strains. The viscoelastic strain was represented as a linear function of viscous strains. Moreover, the Weibull function of the effective stress was introduced to evaluate the damage variables in terms of stiffness reduction. The tensile stress-strain curves, predicted by the proposed model, showed a good agreement with experimental results.

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