Influence of the laminate thickness in low velocity impact behavior of composite material plate (original) (raw)

The response of laminated composite plates and profiles under low-velocity impact load

Composite Structures, 2019

The effect of impact load with low velocity in thin-walled plates and profiles has been investigated. The paper deals with the relation between damage propagation, size and shape as a function of boundary conditions, layer arrangements and impact energy. The structures under consideration were made of eight-layer Glass Fiber Reinforced Polymer (GFRP) laminate with a quasi-isotropic, quasi-orthotropic and angle ply arrangement of layers. The standardised plates predefined to CAI tests and channel section profiles have been subjected to impact load. Based on the performed tests, the impact characteristics have been obtained and compared with the theoretical model (one degree of freedom mass-spring system). Further, despite it not being mentioned in the ASTM 7136 standard, characteristic curves were identified. It was noted that the impacts introducing matrix damages and the partial fracture of the fibres significantly change the course of the Force-Time histories, particularly after the maximum impact force is reached.

Testing and modeling of damages in composite laminates subject to low velocity impact

In recent years, composite materials were used extensively in the most important industries, especially in aerospace industries and aircraft structures due to its high strength, high stiffness, resistance of corrosion, and lightweight. The problem is how to choose the perfect design for composite laminates. And study the effects of modeling of the stacking sequences of composite laminates on failure modes (delamination, matrix cracking, and fiber failure) under the test of low velocity impact. This paper has validating to the experimental results that has published. The composite used was carbon fiber /epoxy (CFRE), (UD ASTM/D6641) as three groups [A, B, C]. It had same material system. The difference was only in stacking sequences as random design. These models were simulated numerically by the commercial software implemented into the FEM/ABAQUS 6.9.1 with subroutine file (VUMAT) a user-define 3D damage model. The results had good agreement with experimental results.

Failure analysis of low velocity impact on thin composite laminates: Experimental and numerical approaches

Composite Structures, 2008

Impact damage development in thick composite laminates

Composites Engineering, 1991

Impact damage tolerance is evaluated for three different thick graphite-epoxy composite material systems which were fabricated as 92-ply composite plates. The systems are designated as brittle, moderately tough and interleaved (very high impact resistance).

Macroscale assessment of low‐velocity impact on hybrid composite laminates

Materialwissenschaft Und Werkstofftechnik, 2021

Composites are usually brittle materials and have low impact properties. Structural dimensions, stacking sequence, ply materials, ply thicknesses and ply angles are standard variables that influence composite‘s performance against impact loads. Stacking sequence in hybrid laminates affects the failure and impact resistance. Failure mechanisms at the low‐velocity impact of a rigid object in hybrid laminates are complex, and the subsurface damage in a composite laminate cannot be detected directly. However, various simulation platforms make it easy to see the impact damage between the plies of laminate. This paper numerically investigated the effect of stack sequence and hybridization of two fiber types against low‐velocity impact. The current study adopted four‐layer composite laminates of carbon and glass fiber layers with a stacking plan [C/C/C/C], [C/G/C/G] and [G/C/G/C], having lay‐up angles as [0°/45°/−45°/90°]. Keeping the impactor mass and the incident velocity constant, the laminates were subjected to low‐velocity impact. The damage contours for a failure mode were recorded and compared at the ply level. The numerical study resulted in impact imitations showing comparisons of the damage contours using Hashin failure criteria. Hybrid laminates display better performance in absorbing impact energies; however, hybrid laminates experienced more subsurface damage due to more impact energy absorption.

Polymer-matrix composites subjected to low-velocity impact: effect of laminate configuration

Effect of laminate configuration on the impact behaviour of different polymer-matrix composites subjected to a transverse central low-velocity point impact load has been studied. For this a 3D transient finite-element analysis code using a modified Hertz law has been used. Quadratic failure criteria have been used to predict in-plane and interlaminar failure initiation. The studies have been carried out with plate dimensions of 150 mmÂ150 mmÂ6 mm with a simply supported boundary condition. For these studies, an incident impact velocity of 3 m/s and an impactor mass of 50 g have been used. Studies have been carried out on different mixed composites, cross-ply laminates, woven-fabric composites and 3D composites. It is observed that mixing of unidirectional and woven-fabric layers leads to the reduction of the failure function.

Numerical and Experimental Analyses of Low Velocity Impact on Thin Composite Laminates

2011

The dynamic behavior of composite laminates is very complex because there are many concurrent phenomena during composite laminate failure under impact load. Fiber breakage, delaminations, matrix cracking, plastic deformations due to contact and large displacements are some effects which should be considered when a structure made from composite material is impacted by a foreign object. Thus, the mechanical material behavior is simulated using a phenomenological model that considers five failure modes: two for fiber-failure (FF) and three for inter-fiber-failure (IFF). In FF modes, the lamina failures under longitudinal tension or compression. In IFF modes, the lamina failures under transverse tension (Mode A), or transverse compression (Mode B or C). Each failure mode has a failure criteria and an associated degradation function that decreases the engineering material properties, turning the process of analysis iterative. The material model is implemented in a sub-routine written in Fortran (UMAT and VUMAT) and used together the finite element package Abaqus for implicit and explicit numerical solution. First, the material parameters are identified and calibrated using case studies based on 3-point bending problem. Thus, finite element analyses are performed for a set of parameters through a Matlab program that controls the parameters variability and generate the results of interest which are then evaluated. After calibration procedure, the material model is used to predict the response of thin disks under impact loads. Finally, the numerical simulations are compared to experimental results, and limitations, as well as potential of material model implemented are discussed.

Impactor mass and specimen geometry effects in low velocity impact of laminated composites

International Journal of Impact Engineering, 1992

There is no proven scaling law for reliably predicting the damage tolerance of brittle composite structures based on the results of laboratory coupon testing. Tests were performed to examine the influence of impactor mass and specimen plan size on the low velocity impact performance of a variety of woven fibre remforced composite laminates. The damage extent was assessed by visual inspection and by ultrasomc c-scanning. It is demonstrated that for a given specimen size the materials subjected to varying impactor masses suffer damage only according to the magnitude of the impact energy--not according to impactor mass or velocity separately. It is shown that increasing the diameter of a specimen increases the impact energy to cause the same damage signature. Two approaches were used to separate the energy absorbed m the damage process from that absorbed elastically by the specimen. A simple procedure is proposed for predicting the impact response of a plate based on a knowledge of the impact performance of a test specimen of different plan size. The results of initial tests investigating this prediction method are encouraging. NOTATION t/

Low-velocity impact tests on carbon/epoxy composite laminates: A benchmark study

Composites Part B: Engineering, 2016

Low-velocity impacts (LVI) on composite laminates pose significant safety issues since they are able to generate extended damage within the structure, mostly delaminations and matrix cracking, while being hardly detectable in visual inspections. The role of LVI tests at the coupon level is to evaluate quantities that can be useful both in the design process, such as the delamination threshold load, and in dealing with safety issues, that is correlating the internal damage with the indentation depth. This paper aims at providing a benchmark of LVIs on quasi-isotropic carbon/epoxy laminates; 2 laminates are tested, 16 and 24 plies and a total of 8 impact energies have been selected ranging from very low energy impacts up to around 30 J. Delamination threshold loads, shape and extension of delaminations as well as post-impact 3D measurements of the impacted surface have been carried out in order to characterize the behavior of the considered material system in LVIs. The analysis of test results relevant to the lowest energies pointed out that large contact force fluctuations, typically associated to delamination onset, occurred but ultrasonic scans did not reveal any significant internal damage. Due to these unexpected results, such tests were further investigated through a detailed FE model. The results of this investigation highlights the detrimental effects of the dissipative mechanisms of the impactor. A combined numerical-experimental approach is thus proposed to evaluate the effective impact energies.

Influence of the laminate thickness in low velocity impact behavior of composite material plate (original) (raw)

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