Showing 4 results for High Velocity Impact
Mohammad Mir, Hadi Sabouri,
Volume 17, Issue 8 (10-2017)
Abstract
In this research, the finite element method have been utilized for investigation the progressive damage in composite laminates. Governing equations on progressive damage in three dimensional stress and strain filed have been expressed based on Hashin's onset of damage and Matzenmiller's progression of failure. The damage equations were coded to make a material model in LS-Dyna. This model could simulate various damage modes such as fiber breakage due to tension or compression, failure due to in-plane shear, crushing and delamination. High velocity impact on woven composite laminates have been analyzed using this material model subroutine. Damage pattern, ballistic limit velocity and growth of damage parameter in different failure modes have been investigated. Also, the occurrence of multi-mode damage at an element and degradation the elastic modulus of the composite material and its softening were studied. In addition, the effect of impact on damage growth at near filed and far filed of the impact zone as well as complete or partial damage of the composite laminate have been investigated. Based on outcomes, number of plies of composite laminate and its thickness have important role on manner of results. Also, for a damaged element, change of failure mode by growth of the damage parameters was observed.
Roohollah Rahmanifard, Davood Alipour,
Volume 18, Issue 1 (3-2018)
Abstract
Since woven fabrics have uniqe characteristrics such as light weight, flexibility, high strength, etc. and they are also capable to be improved for mechanical properties by nano thechnology, it is expectal to gain more efficient composite using intrinsic properties of the ceramic nanoparticles and proper coating method. The uniqe properties of the nanoparticles such as high elastic modulus, high strength to weight ratio etc. as well as participating in defeat mechanisms agains external loadings, can be of the factors reinforcing the textiles. Al2O3-13%TiO2 coatings were deposited on Kevlar Fabric substrates from nanostructured powders using atmospheric plasma spraying (APS). A complete characterization of the feedstock confirmed its nanostructured nature. Coating microstructures and phase compositions were characterized using SEM, and XRD techniques. The microstructure comprised two clearly differentiated regions. One region, completely fused, consisted mainly of nanometer-sized grains of α-Al2O3 with dissolved Ti+4. The other region, partly fused, retained the microstructure of the starting powder and was principally made up of nanometer -sized grains of γ-Al2O3, as confirmed by FESEM. coatings were in average slightly lower than the values for nanostructured coating. The results of tensile testing on kevlar fabrics before and after coating showed that APS could improve tensile strength up to 60%. High velocity impact test (V50) performed on coated fabrics well indicated that their ballistic limit experienced a significant increase. In addition, the results of V50 showed revealed that APS can decrease final weight of new composite panel compared to plain polyetylen panel with identical protection level.
M. Soroush , K. Malekzadehfard, M. Sharavi ,
Volume 19, Issue 9 (9-2019)
Abstract
This paper introduces the initiation and evolution of interlaminar and intralaminar damage in the laminated composite plate under high-velocity impact with the finite element model. Damage in composite layers and delamination between layers are defined based on progressive damage model and cohesive zone modeling. Interlaminar and intralaminar damage initiation are predicted with Hashin criterion and traction-separation law and the damage evolution is predicted with reducing the value of stiffness based on fracture toughness energy that is available in ABAQUS. In this study, needed parameters for the finite element model such as fracture toughness energy are measured experimentally with some tests such as CT and DCB. The finite element model is valid with a velocity comparison of the impactor after impact in experimental impact test with 160J and the numerical simulation. The low percent difference between the experimental and numerical impact results is achieved and thus the needed parameters for simulation is extracted correctly. The present paper introduces a validated, accurate and low-cost finite element model with damage consideration and perforation of impactor for a laminated composite under the high-velocity impact that needed parameters could be measured experimentally.
Hamidreza Zarei, Payam Shahnazar, Mohammad Meskini, Reza Sarkhosh,
Volume 22, Issue 5 (4-2022)
Abstract
Ultra-High molecular weight polyethylene (UHMWPE) fibers are among the strongest and lightest fibers available and are widely used in high-performance ballistic applications. Despite the great advancement of computational analysis in recent years, precise calculations have not been performed to identify the failure of these fibers due to the complexity of the material behavior to impact. In this research, using the most advanced finite element modeling method of composites (Abaqus-Explicit) has been used to study the composite behavior of these fibers subjected to high-velocity projectile impact. Fiber and matrix are designed using solid elements and 3D Hashin failure criterion was used to determine the behavior of the material. Since this criterion is not available in Abaqus, the VUMAT subroutine has been used to implement this criterion. Velocity diagrams and damage evaluation have been reported. To evaluate and validate this method, six samples of Ultra High Molecular Weight Polyethylene (UHMWPE) Composite panels, consisting of 20 and 45 layers, respectively, were experimentally studied by high-velocity projectiles at different velocities. The simulation results are in good agreement with the experimental results.
