Research Progress in High Velocity Penetration into Concrete Theory

With the development of the earth penetration weapon, the research interest has gradually changed from low velocity impact to high velocity or hypervelocity penetration. This paper reviews the the theoretic research status on velocity region ascertaining of penetration, the target material properties near penetration cavity and mass abrasion of projectiles in high velocity penetration, and makes suggestions on the future research.

Download Full-text

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

European Journal of Computational Mechanics ◽

10.13052/ejcm2642-2085.30234 ◽

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.

Download Full-text

Experimental and numerical analysis of high and low velocity impacts against neat and shear thickening fluid (STF) impregnated weave fabrics

EPJ Web of Conferences ◽

10.1051/epjconf/201818301044 ◽

2018 ◽

Vol 183 ◽

pp. 01044

Author(s):

Djalel Eddine Tria ◽

Larbi Hemmouche ◽

Abdelhadi Allal ◽

Abdelkader Benouali

Keyword(s):

High Velocity ◽

Shear Thickening ◽

Force Sensor ◽

Low Velocity Impact ◽

Dynamic Force ◽

Low Velocity ◽

Shear Thickening Fluid ◽

Velocity Impact ◽

Pull Out ◽

The Impact

This investigation aims to study the efficiency of STF impregnated plain-weave fabric made of Kevlar under high and low velocity impact conditions. The shear thickening fluid (STF) was prepared by ultrasound irradiation of silica nanoparticles (diameter ≈30 nm) dispersed in liquid polyethylene glycol polymer. STF impregnation effect was determined from single yarn pull-out test and penetration at low velocity using drop weight machine equipped with hemi-spherical penetrator and dynamic force sensor. Force-displacement curves of neat and impregnated Kevlar were analysed and compared. Also, the STF impregnation effect on Kevlar multilayers was analysed from high velocity impact tests using 9mm FMJ bullet at 390 m/s. After impact, Back face deformation (BFD) of neat and impregnated Kevlar layers were measured and compared. Results showed that STF impregnated fabrics have better energy absorption and penetration resistance as compared to neat fabrics without affecting the fabric flexibility. When relative yarn translations are restricted (e.g. at very high levels of friction), windowing and yarn pull-out cannot occur, and the fibres engaged with the projectile fail in tension that leads to fabric penetration. Microscopy of these fabrics after testing have shown pitting and damage to the Kevlar filaments caused by the hard silica particles used in the STF. Mesoscopic 3D Finite Element models were developed using explicit LS-DYNA hydrocode to account for STF impregnation by employing the experimental results of yarn pull-out tests, low and high velocity impacts. It was found that friction between fibers and yarns increase the dissipation of energy upon impact by restricting fiber mobility, increasing the energy required for relative yarn translations and transferring the impact energy to a larger number of fibers.

Download Full-text

The High-Velocity Impact Behaviour of Kevlar Composite Laminates Filled with Cork Powder

Applied Sciences ◽

10.3390/app10176108 ◽

2020 ◽

Vol 10 (17) ◽

pp. 6108

Author(s):

Ana Martins Amaro ◽

Paulo Nobre Balbis Reis ◽

Ines Ivañez ◽

Sonia Sánchez-Saez ◽

Shirley Kalamis Garcia-Castillo ◽

...

Keyword(s):

High Velocity ◽

Composite Laminates ◽

Bending Strength ◽

Low Velocity Impact ◽

Reinforced Composites ◽

Low Velocity ◽

Velocity Impact ◽

High Velocity Impacts ◽

Minimum Velocity ◽

By Products

The literature reports benefits when the cork powder obtained from industrial by-products is used as the filler of composite laminates. For example, while the fatigue life is insensitive to the presence of cork in the resin, significant improvements are achieved in terms of to low-velocity impact strength. However, in terms of ballistic domain, the literature does not yet report any study about the effect of incorporating powdered cork into resins. Therefore, this study intended to analyse the ballistic behaviour and damage tolerance of Kevlar/epoxy reinforced composites with matrix filled by cork powder. For this purpose, high-velocity impacts were studied on plates of Kevlar bi-directional woven laminates with surfaces of 100 × 100 mm2. It was possible to conclude that the minimum velocity of perforation is 1.6% higher when the cork powder is added to the resin, but considering the dispersion, this small difference can be neglected. In terms of damage areas, they are slightly lower when cork dust is added, especially for velocities below the minimum perforation velocity. Finally, the residual bending strength shows that these composites are less sensitive to impact velocity than the samples with neat resin. In addition to these benefits, cork powder reduces the amount of resin in the composite, making it more environmentally friendly.

Download Full-text

Low Mass-High Velocity and High Mass-Low Velocity Impact Testing on CFRP Specimen Under Equal Impact Energy

10.1115/1.0004890v ◽

2021 ◽

Author(s):

Arnob Banik ◽

Kwek Tze Tan

Keyword(s):

Impact Energy ◽

High Velocity ◽

Impact Testing ◽

Low Velocity Impact ◽

High Mass ◽

Low Velocity ◽

Velocity Impact ◽

Low Mass

Download Full-text

Safety and Reliability Analysis of Composites Under Low Velocity Impact

Volume 3: Structures, Safety and Reliability ◽

10.1115/omae2016-54582 ◽

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.

Download Full-text

Experimental Study of Tensile Preloading Influence on the Mechanical Behaviour of Pseudo-Ductile Hybrid Composite under High-Velocity Impact

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.410.642 ◽

2021 ◽

Vol 410 ◽

pp. 642-648

Author(s):

Nikita A. Olivenko ◽

Oleg A. Kudryavtsev ◽

Mikhail V. Zhikharev

Keyword(s):

Experimental Study ◽

Mechanical Behaviour ◽

Hybrid Composite ◽

High Velocity ◽

Hybrid Composites ◽

Fracture Pattern ◽

Low Velocity Impact ◽

High Velocity Impact ◽

Low Velocity ◽

Velocity Impact

The hybridisation of fibre-reinforced plastics is one of the perspective technological methods that make it possible to reduce the sensitivity of polymer composites to stress concentration and increase their damage tolerance. In this case, hybridisation means a combination of different types of reinforcing fibres in one yarn, one layer or one package. In most published papers, the authors investigated the mechanical behaviour of hybrid fibre-reinforced plastic under static loading or low-velocity impact conditions only. At the same time, statically preloaded structures made of composite materials can also be subjected to high-velocity impact. Tensile or compressive preloading affects not only the amount of energy absorbed by the composite but also changes the deformation and fracture pattern. This paper presents the results of the experimental study of the mechanical behaviour of a woven carbon/aramid hybrid composite under tensile preloading and high-velocity impact. Pre-tensioned specimens of homogeneous and hybrid composites were subjected to a high-velocity impact by a steel spherical projectile with the velocities up to 900 m/s. The experimental results showed that the hybrid composite had the lowest sensitivity of the ballistic limit to the tensile preloading.

Download Full-text

Application of Improved Bingham Model in Braking Large-Mass Unidirectional Impact Loading Problem

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.716-717.623 ◽

2014 ◽

Vol 716-717 ◽

pp. 623-626

Author(s):

Zhi Yin Tang ◽

Gang Wu ◽

Jun Yong Lu ◽

Yan Fei Li ◽

Rui Feng Ma

Keyword(s):

Impact Loading ◽

High Velocity ◽

Mechanical Model ◽

Large Mass ◽

Low Velocity ◽

Damping Force ◽

Bingham Model ◽

Loading Problem ◽

The Impact ◽

Velocity Region

Aimed at braking large-mass unidirectional impact loading problem, the impact loading characteristics has been analyzed and a mechanical model has been established. A new improved Bingham model has been proposed to solve the problem of big error in traditional Bingham model in low-velocity region. Unlike the traditional Bingham model, there are two different kinds of expression of damping force on both low-velocity and high-velocity region in the improved Bingham model. Thus, the accuracy of the model has some improvement, and it has been verified with simulation.

Download Full-text

Inclusion of Strain-Rate Effects in Low Velocity Impact Simulation of Laminated Composites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.465-466.1395 ◽

2013 ◽

Vol 465-466 ◽

pp. 1395-1399

Author(s):

Ainullotfi Abdul-Latif ◽

Mohd Hasrizam Che Man ◽

S. Mansor

Keyword(s):

Strain Rate ◽

Material Properties ◽

Reaction Force ◽

Low Velocity Impact ◽

Static Properties ◽

Low Velocity ◽

Element Analysis ◽

Strain Rate Effects ◽

Velocity Impact ◽

Rate Effects

Composite materials are widely used in aircraft, automotive, marine and railway applications and are exposed to impact loads, in particular low velocity impact. As material properties of composites are affected by strain-rate [, finite element analysis (FEA) by using static properties would not predict their impact behaviour accurately. Thus, the objective of this study was to include strain-rate effects in the simulation of composite laminates under low velocity impact. This was achieved using ABAQUS anisotropic damage model (ADM) by taking account of material properties changes as a function of log strain-rate using user-defined ABAQUS/VUSDFLD subroutine Strain-Rate Dependent ADM (SRD ADM). Results obtained from SRD ADM were validated using simple tensile test done by Okoli [. Subsequently a three-point bending impact event of a simple composite laminate beam by a cylindrical steel impactor was simulated using both the original ABAQUS Static ADM and the user-defined SRD ADM, and compared with experimental impact test results done by [. The results show that reductions in errors of predicted maximum impact reaction force (compared to experimental data) were achieved from 29% using Static ADM to 14% using SRD ADM and from 35% using Static ADM to 15% using SRD ADM respectively for impactor speeds of 2 ms-1 and 5 ms-1.

Download Full-text

Low-velocity impact response of sandwich cylindrical panels with nanotube-reinforced and metal face sheet in thermal environment

The Aeronautical Journal ◽

10.1017/aer.2018.104 ◽

2018 ◽

Vol 122 (1258) ◽

pp. 1943-1966 ◽

Cited By ~ 1

Author(s):

M. R. Bayat ◽

M. Mosavi Mashhadi ◽

O. Rahmani

Keyword(s):

Material Properties ◽

Equations Of Motion ◽

Sandwich Panels ◽

Cylindrical Panel ◽

Impact Response ◽

Low Velocity Impact ◽

Low Velocity ◽

Velocity Impact ◽

Thermal Environments ◽

Cylindrical Panels

ABSTRACTEmploying an analytical method, non-linear low-velocity impact response of carbon nanotube (CNT)-reinforced sandwich cylindrical panels in thermal environments is analysed. Two types of core (i.e. homogenous and functionally graded) are considered for sandwich panels. The face sheets of sandwich panels are multi-layer which consist of CNT-reinforced composite (CNTRC) and metal layers. Micromechanical models are used to estimate the material properties of CNTRCs. A higher-order shear deformation theory with a von Kármán-type of kinematic non-linearity provides the equations of motion. Temperature-dependent material properties are used to include the thermal effects. The equations of motion are solved using a two-step perturbation technique. Existing numerical results in the literature are used to validate the present method. The effect of nanotube volume fraction, material property gradient, impactor initial velocity, geometrical parameters of cylindrical panel, temperature change and edge boundary condition on the impact response of cylindrical panel structures is discussed. The quantitative results and analytical formulations can be helpful in better designing of CNTRC structures subjected to low-velocity impact in thermal environments.

Download Full-text