Effects of the impactor geometrical shape on the non-linear low-velocity impact response of sandwich plate with CNTRC face sheets

2018 ◽  
Vol 22 (4) ◽  
pp. 962-990 ◽  
Author(s):  
A Khalkhali ◽  
N Geran Malek ◽  
M Bozorgi Nejad

In this study, non-linear low-velocity impact response of a simply supported sandwich plate with CNTRC face sheets subjected to the impactors with different geometrical shapes is investigated. It has been assumed that the sandwich plate is made up of two face sheets reinforced with CNTs graded along their thickness as X profile and a homogeneous core. In CNT-reinforced layers, a micromechanical model has been used to obtain the effective material properties and the analysis is performed in the framework of the Reddy's higher order shear deformation theory with regard to thermal effects. An analytical model is proposed to capture the response performance of the three-layer sandwich plates under different thermal environments. Through the proposed analytical study, in order to characterize the contact force between the sandwich plate and the impactors, the modified Hertz contact law is utilized. Rayleigh-Ritz method is applied to the Hamilton principle in order to find the set of equations of motion for the impactor as well as the CNTRC sandwich plate. Afterwards, the solution in the time domain is obtained based on Newmark's numerical time integration scheme. After validating the proposed approach, in order to examine the influences of various involved parameters, different parametric studies are conducted. It has been demonstrated that the variation of the initial kinetic energy as one of the parameters under study has a significant effect on the central displacement, contact force, and indentation in both conical and cylindrical impactors and the change in the radius of the cylinder has an insignificant effect on the central displacement. As well, in the case of equal masses, the cylindrical impactor causes more amount of indentation with respect to conical.

Author(s):  
Apurba Das ◽  
Gopal Agarwal ◽  
Kazuaki Inaba ◽  
Amit Karmakar

Abstract This study presents transient dynamic response of porous and non-porous exponential functionally graded (E-FGM) conical shells subjected to low velocity single and multiple impact. Hertzian contact law in modified form considering permanent indentation is used to calculate the impact response parameters. For finite element formulation eight-noded isoparametric shell element having five degrees of freedom per node is used. The dynamic equations for the low velocity impact problems are solved by Newmark’s time integration scheme. Parametric studies in terms of contact force, initial velocity of impactor, impactor displacement and shell displacement for Stainless Steel-Silicon Nitrite porous and non-porous conical shells (idealized as rotating turbo-machinery blade) under low velocity single and multiple impact are analyzed. Twist angle has significant effect on contact force but has marginal effect on contact duration. Contact force for perfect (porosity free) case is higher than that of porous one and the contact forces are found to decrease with higher porosity factor. Even porous FG conical shell is predicting lower contact force and higher shell displacement than that of uneven porous FG conical shell for a given porosity factor.


2000 ◽  
Vol 122 (4) ◽  
pp. 434-442 ◽  
Author(s):  
U. K. Vaidya ◽  
A. N. Palazotto ◽  
L. N. B. Gummadi

In the current work, sandwich composite structures with innovative constructions referred to as Z-pins, or truss core pins, are investigated. The Z-pin core sandwich construction offers enhanced transverse stiffness, high damage resistance, and multi-functional benefits. The present study deals with analysis of low-velocity impact (LVI) of Z-pin sandwich plate, and experimental studies of compression-after-impact characterization. Experimental studies on LVI of Z-pin sandwich plate considered in the analysis have been reported in Vaidya, et al., 1999, “Low Velocity Impact Response of Laminated Sandwich Composites with Hollow and Foam-Filled Z-Pin Reinforced Core,” Journal of Composites Technology and Research, JCTRER, 21, No. 2, Apr., pp. 84–97, where the samples were subjected to 11, 20, 28, 33, and 40 J of impact energy. The LVI analysis is developed with regards to Z-pin buckling as a primary failure mode (and based on experimental observations). A finite element model accounting for buckling of the pins has been developed and analyzed using ABAQUS. This paper also presents experimental results on compression-after-impact (CAI) studies which were performed on the sandwich composites with Z-pin reinforced core “with” and “without” foam. The experimental LVI tests were performed in Vaidya, et al., 1999, “Low Velocity Impact Response of Laminated Sandwich Composites with Hollow and Foam-Filled Z-Pin Reinforced Core,” Journal of Composites Technology and Research, JCTRER, 21, No. 2, Apr., pp. 84–97. The results indicate that selective use of Z-pin core is a viable idea in utilizing space within the core for sandwich composites in structural applications. [S0094-4289(00)02904-2]


2012 ◽  
Vol 157-158 ◽  
pp. 1135-1138 ◽  
Author(s):  
Mustafizur Rahman ◽  
Evgeny V. Morozov ◽  
Krishna Shankar ◽  
Alan Fien

The present work deals with the finite element modelling of low velocity impact response of different types of composite panels for body armour application. The response of these composites panels including bonded, unbonded and partially bonded laminates has been simulated using non-linear finite element package LS-DYNA. 2D shell elements in LS-DYNA have been used to represent both resin bonded glass fabric targets and dry woven glass fabric panels. The hemispherical shaped projectile is being modelled with 3D solid elements. The results of the numerical analysis showed that the value of contact force for the fully bonded composites panels was significantly higher than that observed for the panels consisting of dry woven glass fabric. However, the corresponding displacement was substantially lower. The similar simulation of the partially bonded composite panels has shown a reduction of both the contact force and the displacement. In addition, it has been shown that the partially bonded composite panels are capable of absorbing higher levels of energy than the rigid panels.


2021 ◽  
pp. 152808372110154
Author(s):  
Ziyu Zhao ◽  
Tianming Liu ◽  
Pibo Ma

In this paper, biaxial warp-knitted fabrics were produced with different high tenacity polyester linear density and inserted yarns density. The low-velocity impact property of flexible composites made of polyurethane as matrix and biaxial warp-knitted fabric as reinforcement has been investigated. The effect of impactor shape and initial impact energy on the impact response of flexible composite is tested. The results show that the initial impact energy have minor effect on the impact response of the biaxial warp-knitted flexible composites. The impact resistance of flexible composite specimen increases with the increase of high tenacity polyester linear density and inserted yarns density. The damage morphology of flexible composite materials is completely different under different impactor shapes. The findings have theoretical and practical significance for the applications of biaxial warp-knitted flexible composite.


2021 ◽  
Vol 150 ◽  
pp. 103813
Author(s):  
Zhiqiang Fan ◽  
Tao Suo ◽  
Taoyi Nie ◽  
Peng Xu ◽  
Yingbin Liu ◽  
...  

2021 ◽  
Vol 1123 (1) ◽  
pp. 012040
Author(s):  
V. Sairam ◽  
S.Kishor Kanna ◽  
P.S.Samuel Ratna Kumar

2016 ◽  
Vol 725 ◽  
pp. 127-131 ◽  
Author(s):  
Kumar V. Akshaj ◽  
P. Surya ◽  
M.K. Pandit

Dent resistance of structures is one of the important design parameters to consider in automotive, aerospace, packaging and transportation of fragile goods, civil engineering and marine industries. It is important to study the dynamic impact response of various combinations of skin and core materials which can provide desired fracture toughness and highest strength to weight ratio for such applications. This paper discusses the low velocity impact response of sandwich structures having unique combination of mild steel as skin material bonded to thermoplastics/PU foam as core material. HDPE, LDPE and polypropylene were the choice of thermoplastics and an optimum combination of materials for the sandwich structure was evaluated using drop-weight experimental set up. It is observed that LDPE is the best choice of core material for the sandwich structures considered.


Sign in / Sign up

Export Citation Format

Share Document