Effects of Curvature and Architecture on Ballistic Performance of UHMWPE Helmets

2019 ◽  
Author(s):  
Timothy G. Zhang ◽  
Lionel R. Vargas-Gonzalez ◽  
James C. Gurganus ◽  
Sikhanda S. Satapathy
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Test Data ◽  
Ballistic Impact ◽  
Ballistic Performance ◽  
Impact Experiments ◽  
Ultra High Molecular Weight

Abstract Ballistic impact experiments were conducted on three types of Ultra-high-molecular-weight polyethylene (UHMWPE) helmets. The three types of helmets had the same geometry, but different fiber orientations in the rear layers. The test data were used to evaluate the effects of architectures. Five impact locations were chosen to understand the effects of impact locations and curvatures. The experimental data from flat and cylindrically curved UHMWPE panels were also used to compare with the helmet test data.

scholarly journals Optimization of soft armor: the response of single-ply para-aramid and ultra-high molecular weight polyethylene fabrics under ballistic impact

2020 ◽  
Vol 90 (15-16) ◽  
pp. 1713-1729 ◽  
Author(s):  
Calvin Ralph ◽  
Lisa Baker ◽  
Edward Archer ◽  
Alistair McIlhagger
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Wave Velocity ◽  
Hybrid System ◽  
Transverse Wave ◽  
Ballistic Impact ◽  
Image Correlation ◽  
Factor C ◽  
The Impact ◽  
Ultra High Molecular Weight

Typical soft armor systems are constructed of multiple layers of a single fabric type. This empirical research sought to begin optimization of these systems through hybridization, sequencing dissimilar armor fabrics to maximize their ballistic protective performance, by first investigating single plies with a spectrum of properties to determine their behavior and response to impact. Eight individual plain weave fabrics with varying yarns and thread counts were manufactured from para-aramid and ultra-high molecular weight polyethylene (UHMWPE) yarns and physical and ballistic characterizations were conducted. The ballistic impact tests established the specific energy absorption (SEA) of each fabric across a range of impact velocities (340–620 m·s–1) and the transverse displacement wave velocity across the rear of the fabric was found using digital image correlation. Low cover factor ( Cfab) fabrics (0.74–0.84) consistently showed faster transverse wave speed than the high Cfab fabrics (0.84–0.96) for any given yarn type. The relative SEA of the fabrics varied dependent on both the impact velocity and number of plies impacted. It was found that lower Cfab fabrics had the highest SEA, critical velocity and transverse wave velocity. UHMWPE fabrics were not considered suitable for a woven hybrid system as they had a significantly lower SEA compared to all the para-aramid fabrics. Results indicate that a hybrid system, when considered as a theoretical spaced system, would benefit from higher Cfab fabrics as rearward layers. However, transverse wave results suggest the lower response of these fabrics may inhibit lower Cfab fabrics at the front of a combined hybridized system.

scholarly journals Experimental and Numerical Investigation of the Effect of Projectile Nose Shape on the Deformation and Energy Dissipation Mechanisms of the Ultra-High Molecular Weight Polyethylene (UHMWPE) Composite

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4208
Author(s):  
Yonghua Shen ◽  
Yangwei Wang ◽  
Zhaopu Yan ◽  
Xingwang Cheng ◽  
Qunbo Fan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Energy Absorption ◽  
Specific Energy ◽  
Ballistic Performance ◽  
Specific Energy Absorption ◽  
Ballistic Resistance ◽  
Nose Shape ◽  
Ultra High Molecular Weight ◽  
Uhmwpe Composite

The effect of projectile nose shape on the ballistic performance of the ultra-high molecular weight polyethylene (UHMWPE) composite was studied through experiments and simulations. Eight projectiles such as conical, flat, hemispherical, and ogival nose projectiles were used in this study. The deformation process, failure mechanisms, and the specific energy absorption (SEA) ability were systematically investigated for analyzing the ballistic responses on the projectile and the UHMWPE composite. The results showed that the projectile nose shape could invoke different penetration mechanisms on the composite. The sharper nose projectile tended to shear through the laminate, causing localized damage zone on the composite. For the blunt nose projectile penetration, the primary deformation features were the combination of shear plugging, tensile deformation, and large area delamination. The maximum value of specific energy absorption (SEA) was 290 J/(kg/m2) for the flat nose projectile penetration, about 3.8 times higher than that for the 30° conical nose projectile. Furthermore, a ballistic resistance analytical model was built based on the cavity expansion theory to predict the energy absorption ability of the UHMWPE composite. The model exhibited a good match between the ballistic resistance curves in simulations with the SEA ability of the UHMWPE composite in experiments.

Unit-cell-based derivation of the material models for armor-grade composites with different architectures of ultra-high molecular-weight polyethylene fibers

2016 ◽  
Vol 7 (4) ◽  
pp. 458-489 ◽  
Author(s):  
Mica Grujicic ◽  
Jennifer Snipes ◽  
S Ramaswami ◽  
Vasudeva Avuthu ◽  
Chian-Fong Yen ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Fiber Reinforcement ◽  
Experimental Investigations ◽  
Transverse Impact ◽  
Ballistic Performance ◽  
Material Models ◽  
Content Type ◽  
Ultra High Molecular Weight ◽  
Polyethylene Fibers

Purpose – Traditionally, an armor-grade composite is based on a two-dimensional (2D) architecture of its fiber reinforcements. However, various experimental investigations have shown that armor-grade composites based on 2D-reinforcement architectures tend to display inferior through-the-thickness mechanical properties, compromising their ballistic performance. To overcome this problem, armor-grade composites based on three-dimensional (3D) fiber-reinforcement architectures have recently been investigated experimentally. The paper aims to discuss these issues. Design/methodology/approach – In the present work, continuum-level material models are derived, parameterized and validated for armor-grade composite materials, having four (two 2D and two 3D) prototypical reinforcement architectures based on oriented ultra-high molecular-weight polyethylene fibers. To properly and accurately account for the effect of the reinforcement architecture, the appropriate unit cells (within which the constituent materials and their morphologies are represented explicitly) are constructed and subjected to a series of virtual mechanical tests (VMTs). The results obtained are used within a post-processing analysis to derive and parameterize the corresponding homogenized-material models. One of these models (specifically, the one for 0°/90° cross-collimated fiber architecture) was directly validated by comparing its predictions with the experimental counterparts. The other models are validated by examining their physical soundness and details of their predictions. Lastly, the models are integrated as user-material subroutines, and linked with a commercial finite-element package, in order to carry out a transient non-linear dynamics analysis of ballistic transverse impact of armor-grade composite-material panels with different reinforcement architectures. Findings – The results obtained clearly revealed the role the reinforcement architecture plays in the overall ballistic limit of the armor panel, as well as in its structural and damage/failure response. Originality/value – To the authors’ knowledge, the present work is the first reported attempt to assess, computationally, the utility and effectiveness of 3D fiber-reinforcement architectures for ballistic-impact applications.

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