Probabilistic Response of Composite Plates for Damage Initiation due to Low Velocity Impact

Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad

The low velocity impact (LVI) result of laminated targets is an imperative study to evaluate its failure for applications to inconsequential structures. The work has extensive applications to off shore and naval industry. Safety and reliability assessment as per the international standards is one of the basic objectives of the study. LVI on composite plates is performed taking the material parameters and loading condition as random variables. Graphite fiber reinforced laminated plates are vulnerable to damage due to impact by foreign objects and in plane loading. In order to evaluate the safe load carrying capacity and the reliability under impact, dynamic analysis of composite plate subjected to LVI is carried out. Probabilistic finite element method (PFEM) is performed to determine the stochastic response. During impact, the in-plane damage modes such as matrix cracking, fiber failure and shear cracking are modeled using a failure criterion. The out of plane de-lamination is modeled using cohesive surfaces. The randomness associated with the system properties due to the inherent scatter in the geometric and material properties and input loads are modeled in a stochastic fashion. Random parameters represent various characteristics appearing in the performance function. The stochastic response and reliability forecast of the system is determined by Gaussian processes response surface method (GPRSM) and validity of method for the present problem is establish using Monte Carlo simulation (MCS) procedure. The safety level qualification is achieved in terms of reliability level targeted.

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad

Stochastic finite-element analysis of composite plates due to low velocity impact (LVI) is studied, considering the material properties (Young's modulii, Poisson's ratio, strengths, and fracture energy) and initial velocity as random parameters. Damage initiation and propagation failure due to matrix cracking are investigated for safety criteria for the LVI. Progressive damage mechanics is employed to predict the stochastic dynamic response of the plates. The Gaussian process response surface method (GPRSM) is presently adopted to determine the probability of failure (Pf). There is a possibility of underestimation of the peak contact force and displacement by 10.7% and 11.03%, respectively, if the scatter in the properties is not considered. The sensitivity-based probabilistic design optimization procedure is investigated to achieve better strength and lighter weight of composite for body armors.


2015 ◽  
Vol 1115 ◽  
pp. 523-526
Author(s):  
Ziamah B. Buang ◽  
S.M. Kashif

Composite materials that have low weight and high strength properties are currently one of the promising materials for a vehicle’s body. However, the effect of low velocity impact on composite may cause failure through matrix cracking, fibre breakage and delamination which may reduce the structure strength. Low velocity impact can be analysed either by experimentation or numerical simulation. Numerical simulation which is also known as finite element analysis can show the degradation of the composite structure properties after an impact loading condition without doing any experimentation. Thus, in this paper, LS-DYNA is the finite element analysis software that is used to simulate a low velocity impact on composite structures.


Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad ◽  
Manander Singh

Low velocity impact on composite plates is studied taking material properties and initial velocity as random parameters. Graphite fiber reinforced composite plates are susceptible to damage due to impact by foreign objects and in plane loading. In order to assess the safe load carrying capacity and the probability of failure under impact, dynamic analysis of composite plate subjected to low velocity impact is carried out. Finite element method is used to study impact. During impact, the in-plane damage modes such as matrix cracking, fiber failure and shear cracking are modeled using a failure criterion. The out of plane de-lamination is modeled using cohesive surfaces. The uncertainties associated with the system properties due to the inherent scatter in the geometric and material properties and input loads are modeled in a probabilistic fashion. Random parameters represent various characteristics appearing in the limit state function. The probabilistic analysis and reliability prediction of the system is carried out using Gaussian response surface method and validity of method for the present problem is establish using Monte Carlo simulation (MCS) procedure. Sensitivity analysis of the probability of failure with respect to random parameters considered is an important study for design optimization. The safety level qualification is achieved in terms of reliability level targeted. The mean and standard deviations of random variables show an appreciable influence on the probabilistic failure. Systematic changes in the input parameters are governed by the probabilistic sensitivity tools to achieve target reliability.


2015 ◽  
Vol 1115 ◽  
pp. 560-563
Author(s):  
Nazwan Ghazali ◽  
Mohamed Shaik Dawood ◽  
S.M. Kashif

Fiber reinforced composite materials are known to have poor tolerance to impact loads. Damages can be observed in the forms of matrix crack, fiber failure and delamination. In the case of low velocity impact, delamination is often a major concern due to its hidden nature. In this work, the effects of piezoelectric actuation on delamination in composite plates subjected to low velocity impact have been studied using LS-DYNA. It was found that, piezoelectric actuators can be used to reduce delamination in composite laminates. This was achieved by actuating the laminate to curve in the opposite direction of the incoming impact load.


2021 ◽  
Vol 2133 (1) ◽  
pp. 012008
Author(s):  
Xiaozhou Feng ◽  
Xiufang Wang ◽  
Changwei Zhou ◽  
Jianmin Zhang

Abstract A mechanical model of laminated plates subjected to low velocity impact is proposed in this paper. The model studies the attenuation of impactor velocity affected by air resistance, intra-laminar damage initiation based strain, intra-laminar damage evolution based on damage parameters and delamination damage. Based on this mechanical model and ABAQUS platform, the experiment of Shi is numerically simulated. It is found that the predicted contact force, energy absorption and delamination damage of laminates are in good agreement with the experimental results, indicating that the established mechanical model can be used to predict the mechanical response and damage characteristics of composite laminates subjected to low velocity impact.


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