Papers by Keyword: Penetration

Abstract: The paper addresses the issues of subjective and instrumental quality assessment of flaw detection materials by Sherwin, Bycotest, Spotcheck, Chemetall and R-test penetrant materials using non-metallic test panels and software code.

Abstract: Based on the AUTODYN-2D nonlinear dynamics platform, numerical simulations andexperiments are conducted to study the effect of 44mm small-caliber shaped charge on penetrationcharacteristics. Copper as the suitable material is chosen for small-caliber shaped charges, and theinfluence of the cone and the thickness of liner on the penetration of the jet into the steel target isobtained. The results show that the penetration depth decreases with the growth of the cone angle.Moreover, with the thickness of liner increasing, the penetration depth increases first and thendecreases. Based on the numerical simulation, structural parameters of the double cone liners wereoptimized: the optimum thickness liner was 1.2mm, and the optimal upper and lower cone of thedouble-cone liner was 40° and 60°. Besides, a static explosion test that the optimized double coneof the copper-type liner penetrated 45# steel targets is performed to verify the numerical simulation.

Abstract: The paper considers the mathematical model of liquid motion in straight-line capillaries. The proposed mathematical model shows the liquid motion in slit-like capillaries, with regard to the density, viscosity and surface tension of liquids, the capillary size, and the angle of capillary inclination to the horizontal. The modeling results are proved by full-scale experiments.

Abstract: The purpose of this study is development of gun-bullet protect board. The collision test was executed in such a way to launch a bullet and collide to the target by the air gun. The mock bullet made of brass was used as the projectile. The collision behaviors of polycarbonate (PC) target board were clarified. Next, the analysis of gun bullet collision between the bullet and PC board has been practiced by non-liner dynamic FEM commercial software (AUTODYN^TM) and an effective bullet protection board is designed based on this analytical result.

Abstract: Composite material has been widely used in the field of bulletproof, and many people have studied it. With the development of the large commercial finite element software, it provides a broad platform for the research of the bullet proof performance of the composite material. The finite element software is used to simulate the effect of different factors on the ballistic performance. The dynamics simulation model of orthotropy is established by Abaqus/Explicit Hashin damage criterion. The velocity of the projectile is changed with time in the process of penetrating the composite target. The theoretical and numerical simulation of the ballistic limit velocity of projectile penetration are compared by the simulation of the composite laminate. The simulation results agree well with the theoretical calculations, and the model is proved to be reasonable and effective. It provides a good basis for the study on the damage of fiber reinforced composite target

Abstract: Environmental pollution caused by abundant wastes from agricultural activities has increased in recent years because of increased productivity. Agricultural waste recycling has been employed to solve this problem. Coconut shell charcoal (CSC) ash is a by-product of coconut shell (CS) used as a bitumen modifier to enhance the properties of the binder. This study investigated the effect of fineness charcoal ash from CS on the rheological properties of bitumen. Penetration, softening point, and viscosity tests were performed to determine the properties of the binder. Laboratory simulation of aging called rolling thin film oven test was applied in this study. CSC at different sizes (< 75μm, 75–150μm, and 150–300μm) was added to replace bitumen 60/70 PEN at 0%, 10%, 15%, and 20% by weight of the binder, respectively. Result showed that the bitumen became more viscous and that the softening point of bitumen increased, whereas the rate of penetration decreased when CSC was incorporated. CSC at a proper amount improved the resistance of bitumen to temperature susceptibility. In addition, the modification of bitumen can relieve the effect of aging. Modified bitumen shows better result when incorporated with the finest particle (< 75μm) of CSC compared with other sizes.

Abstract: To understand the mechanical behavior of the concrete structures, one must analyze deformation and fracture of the interfaces between the constituents of the material that the structure is made of. Criteria for predicting the crack growth along an interface, based on the linear elastic fracture mechanics concept, applied for the cement substrate/aggregate interface, are presented in this paper. The two possible directions of the interfacial crack growth – the crack propagation along the interface and the crack kinking away from the interface are considered, with the corresponding energy release rates. For the case of the crack approaching the interface from one of the materials – cement, the competition between the crack deflecting into the interface and the crack penetrating the interface is considered with the corresponding energy release rates.

Abstract: Long rod has strong ability of penetrating into targets with high velocity because of the big ratio of L/D. In the process of the penetration, the resistance of target is so big that the deformation of the head of the projectile is severe. There are many factors influence the process, which make it difficult to get analytic solutions. In this paper, we propose a simplified calculation method which considering engineering strain of the head of projectile. And the rigid-plastic model was used to describe the constitutive model of projectiles. The relationship between the engineering strain of the mushroom area and velocity was analyzed, which is exponential. Then, combined with cavity expansion theory, the calculation results about the DOP are in good agreements with the experimental results. At last, there are numerical simulations about the relative experiments, and the results obtained from numerical simulations show the deformation of the projectile and the depth of the penetration, which are in good agreement with the theoretical calculation and experiments.

Abstract: This paper aims to establish a model that considers the penetration resistance caused by the constraint effects of steel reinforcements on concrete. Firstly, based on the experiment phenomena that reinforcements increase the toughness and tensile strength of concretes, the fitting relational expression between toughness of reinforced concrete and ratio of reinforcement was used to improve the Griffith yield criterion for reinforced concrete. Then, the dynamic spherical cavity expansion analysis was developed using the improved Griffith yield criterion as constitutive model and the dilation equation as equation of state, and the response regions were consisted of six distinct zones: cavity, compaction zone, dilation zone, radially cracked zone, elastic zone and undisturbed zone. This dynamic analysis considered the compression and dilation of concretes at the same time and was applicable to the penetration problem of reinforced concrete target. At last, based on the theoretical model of this paper, the experiments of projectiles with different weights penetrating into reinforced concrete targets with different reinforcement ratios were calculated using penetration analysis method of rigid projectiles. The comparison results showed that the theoretical analysis model of this paper can be used to predict the depth of penetration and other physical parameters such as velocity and deceleration with certain rationality.

Abstract: Skin laceration injury caused by a penetration of small curvature edge frequently occurs in a domestic accident. An assessment method for this injury is necessary in order to develop a safer manufactured product. To assess the risk of skin laceration injury in a penetration accident, a skin simulant made from silicone rubber was proposed. However, mechanical responses of this skin simulant under dynamic penetration loading have not yet been investigated. In this study, a drop weight penetration test device was developed in order to simulate penetration accidents under impact velocities of over 1 m/s. The device was then used for investigating the dynamic responses of skin simulant against several blades with different tip curvature radii. Load, penetration depth, impulse and energy at rupture were then determined from the test results. Load and penetration depth at rupture increased with the increase of tip curvature radius of the blades. Furthermore, the drop weight test result showed larger response compared to the quasi-static test result which might be caused by the viscous effect and the polymer characteristics such as cross-linking of the skin simulant.