The objective of this work is to study the effectiveness of an advanced coating material, polyurea, as a blast mitigation tool for steel components. The response of polyurea coated steel components under blast loading is studied using the explicit LS-DYNA code with appropriate loading time histories supplied using a computational fluid dynamics (CFD) code developed at Penn State University, PUM...

Fly ash, which consists of hollow particles with porous shells, was introduced into polyurea elastomer. A one-step method was chosen to fabricate pure polyurea and the polyurea matrix for the composites based on Isonate® 2143L (diisocyanate) and Versalink® P-1000 (diamine). Scanning electron microscopy was used to observe the fracture surfaces of the composites. Particle size and volume fractio...

This article presents the results of a series of experiments performed to assess the dynamic response of circular monolithic steel and steel–polyurea bilayer plates to impulsive loads. A convenient technique to enhance the energy absorption capability of steel plates and to improve their resistance to fracturing in dynamic events, is to spray-cast a layer of polyurea onto the plates. Since poly...

We present the results of our numerical simulation of the dynamic response and deformation of 1 m diameter circular DH-36 steel plates and DH-36 steel-polyurea bilayers, subjected to blast-like loads. Different thicknesses of the polyurea are considered and the effect of polyurea thickness on the performance of steel plates under blast loads is investigated. For each polyurea thickness, we have...

In this paper, we present and discuss the results of our numerical simulation of the dynamic response and failure modes of circular DH-36 steel plates and DH-36 steel–polyurea bilayers, subjected to impulsive loads in reverse ballistic experiments. In our previous article, we reported the procedure and results of these experiments [MR Amini, JB Isaacs, S Nemat-Nasser. Experimental investigation...

Polyurea coatings on steel form tough, flexible and chemically resistant surfaces, making them ideal for a variety of applications. An important issue for polyurea coatings in some cases is their adhesion to steel under various loading conditions in aggressive environments. In this paper, adhesion was examined using steel/polyurea/steel sandwich specimens and interfacial fracture mechanics. The...

Polyurea is an alternating copolymer with excellent viscoelastic properties for dissipating shock and impact loads; however, a molecular-level understanding of how its chemistry relates to its performance remains elusive. While molecular dynamics simulations can in theory draw connections between molecular structure and viscoelastic properties, in practice the long relaxation times associated w...

An in situ polycondensation approach was applied to functionalize multiwalled carbon nanotubes (MWNTs), resulting in various linear or hyperbranched polycondensed polymers [e.g., polyureas, polyurethanes, and poly(urea-urethane)-bonded carbon nanotubes]. The quantity of the grafted polymer can be easily controlled by the feed ratio of monomers. As a typical example, the polyurea-functionalized ...

Purpose – The purpose of this paper is to address the problems of interaction of tensile stress-waves with polyurea/fused-silica and fused-silica/polyurea interfaces, and the potential for the accompanying interfacial decohesion. Design/methodology/approach – The problems are investigated using all-atom non-equilibrium molecular-dynamics methods and tools. Before these methods/tools are employe...

Novel polyureas with soft segments based on a difunctional amine, Versalink P-1000, and hard segments based on Isonate 143L, which is a mixture of difunctional and trifunctional isocyanates, were synthesized. The stoichiometric ratio of Isonate 143L to Versalink P-1000 in the polyurea material system was incrementally varied. The properties of the resultant polyurea formulations were characteri...