Safety and Reliability Analysis of Composites Under Low Velocity Impact

2016 ◽  
Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad ◽  
Manander Singh
Keyword(s):  
Material Properties ◽  
Limit State ◽  
Composite Plates ◽  
Probability Of Failure ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
State Function ◽  
Random Parameters ◽  
Low Velocity ◽  
Velocity Impact

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.

Simulation of Low Velocity Impact Test on Carbon/Epoxy Composite Plates

2015 ◽  
Vol 1115 ◽  
pp. 523-526
Author(s):  
Ziamah B. Buang ◽  
S.M. Kashif
Keyword(s):  
Numerical Simulation ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Structures ◽  
Composite Plates ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Element Analysis ◽  
Velocity Impact

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.

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

2018 ◽  
Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad
Keyword(s):  
Composite Plates ◽  
Laminated Plates ◽  
International Standards ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Stochastic Response ◽  
Low Velocity ◽  
Fiber Failure ◽  
Velocity Impact ◽  
Damage Initiation

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.

Probabilistic Failure of Graphite Epoxy Composite Plates Due to Low Velocity Impact

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad
Keyword(s):  
Damage Mechanics ◽  
Optimization Procedure ◽  
Composite Plates ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Stochastic Dynamic ◽  
Low Velocity ◽  
Element Analysis ◽  
Velocity Impact ◽  
Damage Initiation

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.

Probabilistic Oblique Impact Analysis of Functionally Graded Plates – A Multivariate Adaptive Regression Splines Approach

2021 ◽  
Author(s):  
P. K. Karsh ◽  
Bindi Thakkar ◽  
R. R. Kumar ◽  
Vaishali ◽  
Sudip Dey
Keyword(s):  
Material Properties ◽  
Mass Density ◽  
Plate Thickness ◽  
Functionally Graded ◽  
Multivariate Adaptive Regression Splines ◽  
Low Velocity Impact ◽  
Fe Model ◽  
Low Velocity ◽  
Velocity Impact ◽  
Mars Model

Purpose: To investigate the probabilistic low-velocity impact of functionally graded (FG) plate using the MARS model, considering uncertain system parameters. Design/methodology/application: The distribution of various material properties throughout FG plate thickness is calculated using power law. For finite element (FE) formulation, isoparametric elements with eight nodes are considered, each component has five degrees of freedom. The combined effect of variability in material properties such as elastic modulus, modulus of rigidity, Poisson’s ratio, and mass density are considered. The surrogate model is validated with the FE model represented by the scatter plot and the probability density function (PDF) plot based on Monte Carlo simulation (MCS). Findings: The outcome of the degree of stochasticity, impact angle, impactor’s velocity, impactor’s mass density, and point of impact on the maximum value of contact force (CFmax ), plate deformation (PDmax), and impactor deformation (IDmax ) are determined. A convergence study is also performed to determine the optimal number of the constructed MARS model’s sample size. Originality/value: The results illustrate the significant effects of uncertain input parameters on FGM plates’ low-velocity impact responses by employing a surrogate-based MARS model.

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