Progressive Failure Analysis on Textile Composites

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140707/1/6.2014-0157.pd

Experimental investigation of a novel blast wave mitigation device

A novel blast wave mitigation device was investigated experimentally in this paper. The device consists of a pistoncylinder assembly. A shock wave is induced within the cylinder when a blast wave impacts on the piston. The shock wave propagates inside the device and is reflected repeatedly. The shock wave propagation process inside the device lengthens the duration of the force on the base of the device to several orders of magnitude of the duration of the blast wave, while it decreases the maximum pressure over an order of magnitude. Two types of experiments were carried out to study the blast wave mitigation device. The first type of experiments was done with honeycomb structures protected by the blast wave mitigation device. Experimental results show that the device can adequately protect the honeycomb structure. A second type of experiments was done using a Hopkinson bar to measure the pressure transmitted through the blast wave mitigation device. The experimental results agree well with results from a theoretical model

Experimental Investigation of a Novel Blast Wave Mitigation Device

A novel blast wave mitigation device was investigated experimentally in this paper. The device consists of a piston-cylinder assembly. A shock wave is induced within the cylinder when a blast wave impacts on the piston. The shock wave propagates inside the device and is reflected repeatedly. The shock wave propagation process inside the device lengthens the duration of the force on the base of the device to several orders of magnitude of the duration of the blast wave, while it decreases the maximum pressure over an order of magnitude. Two types of experiments were carried out to study the blast wave mitigation device. The first type of experiments was done with honeycomb structures protected by the blast wave mitigation device. Experimental results show that the device can adequately protect the honeycomb structure. A second type of experiments was done using a Hopkinson bar to measure the pressure transmitted through the blast wave mitigation device. The experimental results agree well with results from a theoretical model

A ballistic material model for continuous-fiber reinforced composites

A ply-level material constitutive model for plain-weave composite laminates has been developed to enable computational analyses of progressive damage/failure in the laminates under high velocity ballistic impact conditions. In this model, failure-initiation criteria and damage evolution laws are introduced to account for the major fiber-failure modes (tensile, compressive, punch shear and crush loading). In addition, two matrices related failure modes (in-plane shear and through the thickness delamination) are also accounted for. These types of fiber and matrix failure modes are commonly observed during a ballistic event. The composite-material model has been implemented within LS-DYNA as a user-defined material subroutine and used successfully to predict the damage and ballistic behavior of composite laminates subjected to various ballistic impact conditions. It is hoped that the availability of this material model will help facilitate the development of composite structures with enhanced ballistic survivability

Acoustoelastic Wave Velocity in Metal Matrix Composite under Thermal Loading

It is well known that microstresses are developed in a composite subjected to a temperature change due to the mismatch in thermal expansion between the fibers and the matrix. The stresses in the matrix can be large enough to cause the matrix to yield and deform plastically. The nonlinear thermal behavior is evidenced by experimentally observed thermal hysteresis in a metal matrix composite under thermal cycling [1]. Obviously, the thermal hysteresis plays an important role on the dimensional stability of the metal matrix composites, especially for graphite fiber reinforced composites.</p

Dynamic modeling for rate-dependent and mode-dependent cohesive interface failure analysis

Accurate modeling of interface failure represents an important consideration for analysis cases such as adhesive bonds or phase interface failure of inhomogeneous materials. In the current work, a cohesive element based model for interface failure has been developed in the context of a butterfly-type Hopkinson Bar interface specimen. Simulation has enabled insight into the dynamic in-situ stress state and crack growth under impact for property determination and test specimen evaluation. A failure criterion has been successfully employed and agrees closely with experimental results at multiple strain rates. Strain rate effects and fracture mode effects are implemented to modify the allowable strain to failure at the interface. Calculated fracture toughness values and crack propagation rates have compared closely to published experimental results at multiple strain rates. An analytical parametric evaluation of the interface failure model has been performed to illustrate the relative importance of material properties and failure behavior. </jats:p

Impact damage on a thin glass plate with a thin polycarbonate backing

We present experimental and computational results for the impact of a spherical projectile on a thin glass plate with a thin polycarbonate backing plate, restrained in a metal frame, or in the absence of the frame. We analyze the dependence of the damage patterns in the glass plate on the increasing impact velocities, from 61 m/s to 200 m/s. Experimental results are compared with those from peridynamic simulations of a simplified model. The main fracture patterns observed experimentally are captured by the peridynamic model for each of the three projectile velocities tested. More accurate implementation of the actual boundary conditions present in the experiments will likely further improve modeling of brittle damage from impact on a multi-layered system. The peridynamic computational model sheds light into the early stages of the complex brittle damage evolution in the glass layer, and the influence of boundary conditions on the dynamic fracture process

Experimental investigation of a novel blast wave mitigation device

A novel blast wave mitigation device was investigated experimentally in this paper. The device consists of a pistoncylinder assembly. A shock wave is induced within the cylinder when a blast wave impacts on the piston. The shock wave propagates inside the device and is reflected repeatedly. The shock wave propagation process inside the device lengthens the duration of the force on the base of the device to several orders of magnitude of the duration of the blast wave, while it decreases the maximum pressure over an order of magnitude. Two types of experiments were carried out to study the blast wave mitigation device. The first type of experiments was done with honeycomb structures protected by the blast wave mitigation device. Experimental results show that the device can adequately protect the honeycomb structure. A second type of experiments was done using a Hopkinson bar to measure the pressure transmitted through the blast wave mitigation device. The experimental results agree well with results from a theoretical model