Linking Theory to Practice: Predicting Ballistic Performance from Mechanical Properties of Aged Body Armor

2020 ◽  
Vol 125 ◽  
Author(s):  
Amanda L. Forster ◽  
Dennis D. Leber ◽  
Amy Engelbrecht-Wiggans ◽  
Virginie Landais ◽  
Allen Chang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Accelerated Aging ◽  
Test Methods ◽  
The Body ◽  
Body Armor ◽  
Ballistic Limit ◽  
Ballistic Performance ◽  
Validation Data ◽  
Data Set ◽  
Ballistic Resistance

It has long been a goal of the body armor testing community to establish an individualized, scientific-based protocol for predicting the ballistic performance end of life for fielded body armor. A major obstacle in achieving this goal is the test methods used to ascertain ballistic performance, which are destructive in nature and require large sample sizes. In this work, using both the Cunniff and Phoenix-Porwal models, we derived two separate but similar theoretical relationships between the observed degradation in mechanical properties of aged body armor and its decreased ballistic performance. We present two studies used to validate the derived functions. The first correlates the degradation in mechanical properties of fielded body armor to the degradation produced by a laboratory accelerated-aging protocol. The second examines the ballistic resistance and the extracted-yarn mechanical properties of new and laboratory-aged body armor made from poly(p-phenylene-2,6-benzobisoxazole), or PBO, and poly(p-phenylene terephthalamide), or PPTA. We present correlations found between the tensile strengths of yarns extracted from armor and the ballistic limit (V50) when significant degradation of the mechanical properties of the extracted yarns was observed. These studies provided the basis for a validation data set in which we compared the experimentally measured V50 ballistic limit results to the theoretically predicted V50 results. The theoretical estimates were generally shown to provide a conservative prediction of the ballistic performance of the armor. This approach is promising for the development of a tool for fielded armor performance surveillance relying upon mechanical testing of armor coupon samples.

Ballistic Resistant Body Armor: Contemporary and Prospective Materials and Related Protection Mechanisms

2009 ◽  
Vol 62 (5) ◽  
Author(s):  
N. V. David ◽  
X.-L. Gao ◽  
J. Q. Zheng
Keyword(s):  
Natural Fiber ◽  
Resistance Mechanisms ◽  
The Body ◽  
Body Armor ◽  
Military Operations ◽  
Ballistic Performance ◽  
Protection Mechanisms ◽  
And Performance ◽  
Materials Used ◽  
Energy Absorbing

Modern military operations, technology-driven war tactics, and current on-street weapons and ammunition necessitate the development of advanced ballistic protection body armor systems that are damage-resistant, flexible, lightweight, and of great energy absorbing capacity. A number of studies related to new concepts and designs of body armor materials (including those derived from or inspired by nature) have been conducted in the past two decades to meet the new demands. Ballistic fabrics, ceramics, and laminated composites are among the leading materials used in modern body armor designs, and nano-particle and natural fiber filled composites are candidate materials for new-generation body armor systems. Properties and ballistic resistance mechanisms of such materials have been extensively investigated. Based on a comprehensive and critical review of the advances and findings resulting from these investigations, a comparative study on design, protection mechanisms, and performance evaluation of various types of anti-ballistic body armor is presented in this paper. Body armor systems made from different materials and exhibiting distinct ballistic energy absorption mechanisms are discussed, and key factors that influence the ballistic performance and energy absorbing mechanisms of the body armor systems are identified.

Multi-layer pattern creation for seamless front female body armor panel using angle-interlock woven fabrics

2016 ◽  
Vol 87 (3) ◽  
pp. 381-386 ◽  
Author(s):  
D Yang ◽  
X Chen
Keyword(s):  
Mathematical Model ◽  
Female Body ◽  
Woven Fabrics ◽  
The Body ◽  
Body Armor ◽  
Woven Fabric ◽  
Front Panel ◽  
Ballistic Performance ◽  
Novel Approach ◽  
The Relationship

Angle-interlock woven fabric offers an option for making female body armor as it can form integrally the required dome shapes because of its extraordinary moldability and satisfactory ballistic performance. A mathematical model is created to determine the pattern geometry for the front panel of female body armor, and the front panel can be quickly created using this mathematical model. However, the body armor is multi-layer, which indicates that the relationship between the thickness of the fabric and the pattern block projection for different layers of fabric needs to be investigated, in order to create the whole panel, to improve this novel approach for making seamless female body armor with satisfactory ballistic performance.

scholarly journals Estimating the Body Weight of Florida Panthers From Standard Morphometric Measurements

2017 ◽  
Vol 8 (2) ◽  
pp. 618-624 ◽  
Author(s):  
Tad M. Bartareau
Keyword(s):  
Body Weight ◽  
Puma Concolor ◽  
The Body ◽  
Similar Proportion ◽  
Theoretic Approach ◽  
Estimation Model ◽  
Morphometric Measurements ◽  
Validation Data ◽  
Data Set ◽  
The Relationship

Abstract Measuring a mammal's body weight has importance in understanding reproductive biology, ecology, and population health. It can be impractical for a researcher to measure the body weight of mammals when equipment needed to weigh individuals is inadequate or unavailable. My objective here was to develop a model to accurately estimate the body weight of Florida panthers Puma concolor coryi Bang based on the relationship between scale weight, sex, and standard morphometric measurement predictor variables obtainable in the field. I used an information-theoretic approach to evaluate simple and multiple linear regression models with 70% of the data, and validated the best model in the set using the remaining 30%. Individuals maintained a similar proportion of body weight to body length, chest girth2, and neck girth measurements, and the relationship was consistent between sexes. My best model explained 94% of the variation in body weight of Florida panthers, and the observed and estimated body weights in the validation data set were not different. The 95% confidence interval on the bias of the estimated body weight ranged from −1.1 to 0.9 kg in the validation data set. This body-weight estimation model will enable retrospective estimates of the body weight of Florida panthers in cases where standard morphometric measurements are available but the individuals were not weighed.

Characterizing the Interaction Among Bullet, Body Armor, and Human and Surrogate Targets

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Weixin Shen ◽  
Yuqing Niu ◽  
Lucy Bykanova ◽  
Peter Laurence ◽  
Norman Link
Keyword(s):  
Energy Absorption ◽  
High Speed ◽  
Target Material ◽  
The Body ◽  
Body Armor ◽  
Second Phase ◽  
Model Calculations ◽  
Ballistic Resistance ◽  
Third Phase ◽  
Protective Effectiveness

This study used a combined experimental and modeling approach to characterize and quantify the interaction among bullet, body armor, and human surrogate targets during the 10–1000 μs range that is crucial to evaluating the protective effectiveness of body armor against blunt injuries. Ballistic tests incorporating high-speed flash X-ray measurements were performed to acquire the deformations of bullets and body armor samples placed against ballistic clay and gelatin targets with images taken between 10 μs and 1 ms of the initial impact. Finite element models (FEMs) of bullet, armor, and gelatin and clay targets were developed with material parameters selected to best fit model calculations to the test measurements. FEMs of bullet and armor interactions were then assembled with a FEM of a human torso and FEMs of clay and gelatin blocks in the shape of a human torso to examine the effects of target material and geometry on the interaction. Test and simulation results revealed three distinct loading phases during the interaction. In the first phase, the bullet was significantly slowed in about 60 μs as it transferred a major portion of its energy into the body armor. In the second phase, fibers inside the armor were pulled toward the point of impact and kept on absorbing energy until about 100 μs after the initial impact when energy absorption reached its peak. In the third phase, the deformation on the armor’s back face continued to grow and energies inside both armor and targets redistributed through wave propagation. The results indicated that armor deformation and energy absorption in the second and third phases were significantly affected by the material properties (density and stiffness) and geometrical characteristics (curvature and gap at the armor-target interface) of the targets. Valid surrogate targets for testing the ballistic resistance of the armor need to account for these factors and produce the same armor deformation and energy absorption as on a human torso until at least about 100 μs (maximum armor energy absorption) or more preferably 300 μs (maximum armor deformation).

scholarly journals Advancement in Graphene-Based Materials and Their Nacre Inspired Composites for Armour Applications—A Review

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1239
Author(s):  
Jesuarockiam Naveen ◽  
Mohammad Jawaid ◽  
Kheng Lim Goh ◽  
Degalhal Mallikarjuna Reddy ◽  
Chandrasekar Muthukumar ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Light Weight ◽  
Ballistic Limit ◽  
Two Dimensional ◽  
Ballistic Performance ◽  
Ballistic Resistance ◽  
High Toughness ◽  
Body Armour ◽  
Military Conflicts ◽  
Self Defence

The development of armour systems with higher ballistic resistance and light weight has gained considerable attention as an increasing number of countries are recognising the need to build up advanced self-defence system to deter potential military conflicts and threats. Graphene is a two dimensional one-atom thick nanomaterial which possesses excellent tensile strength (130 GPa) and specific penetration energy (10 times higher than steel). It is also lightweight, tough and stiff and is expected to replace the current aramid fibre-based polymer composites. Currently, insights derived from the study of the nacre (natural armour system) are finding applications on the development of artificial nacre structures using graphene-based materials that can achieve high toughness and energy dissipation. The aim of this review is to discuss the potential of graphene-based nanomaterials with regard to the penetration energy, toughness and ballistic limit for personal body armour applications. This review addresses the cutting-edge research in the ballistic performance of graphene-based materials through theoretical, experimentation as well as simulations. The influence of fabrication techniques and interfacial interactions of graphene-based bioinspired polymer composites for ballistic application are also discussed. This review also covers the artificial nacre which is shown to exhibit superior mechanical and toughness behaviours.

scholarly journals Rheology Based Design of Shear Thickening Fluid for Soft Body Armor Applications

2019 ◽  
Vol 64 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Balasubrahmanya Harish Manukonda ◽  
Victor Avisek Chatterjee ◽  
Sanjeev Kumar Verma ◽  
Debarati Bhattacharjee ◽  
Ipsita Biswas ◽  
...  
Keyword(s):  
Particle Size ◽  
Shear Thickening ◽  
High Strength ◽  
Packing Fraction ◽  
Continuous Phase ◽  
Body Armor ◽  
Rheological Characterization ◽  
Ballistic Performance ◽  
Ballistic Resistance ◽  
Shear Thickening Fluids

The ballistic resistance of high-strength fabrics improves upon impregnation with Shear Thickening Fluids (STFs). The performance of such STF treated fabrics depends on the rheological properties of the STF which in turn are governed by the physicochemical properties of the STF. The present study utilizes rheological characterization of shear thickening silica-polyethylene glycol dispersions (of different material configurations in terms of packing fraction, particle size and continuous phase viscosity) to assess their performance and obtain the best STF material configuration for ballistic body armor applications based on the design criteria proposed herein. The ballistic performance assessment results showed that the STFs with high packing fractions which thicken discontinuously, are highly effective compared to the continuously shear thickening fluids. Furthermore, the use of smaller particle size dispersed phase in the STF formulation was determined to be economical. Also, the use of lower molecular weight dispersion medium was suggested as it allows for a broader working temperature range of the STF. Additionally, the technological issues associated with the development and the practical application of STF-Armor were addressed.

scholarly journals Rheological Characterization of Next-Generation Ballistic Witness Materials for Body Armor Testing

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 447
Author(s):  
Ran Tao ◽  
Kirk Rice ◽  
Anicet Djakeu ◽  
Randy Mrozek ◽  
Shawn Cole ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Temperature Sensitivity ◽  
Thermomechanical Behavior ◽  
Oscillatory Shear ◽  
Body Armor ◽  
Resistance Testing ◽  
Rheological Characterization ◽  
Ballistic Performance ◽  
Small Amplitude Oscillatory Shear

Roma Plastilina No. 1 (RP1), an artist modeling clay that has been used as a ballistic clay, is essential for evaluation and certification in standards-based ballistic resistance testing of body armor. It serves as a ballistic witness material (BWM) behind the armor, where the magnitude of the plastic deformation in the clay after a ballistic impact is the figure of merit (known as “backface signature”). RP1 is known to exhibit complex thermomechanical behavior that requires temperature conditioning and frequent performance-based evaluations to verify that its deformation response satisfies requirements. A less complex BWM formulation that allows for room-temperature storage and use as well as a more consistent thermomechanical behavior than RP1 is desired, but a validation based only on ballistic performance would be extensive and expensive to accommodate the different ballistic threats. A framework of lab-scale metrologies for measuring the effects of strain, strain rate, and temperature dependence on mechanical properties are needed to guide BWM development. The current work deals with rheological characterization of a candidate BWM, i.e., silicone composite backing material (SCBM), to understand the fundamental structure–property relationships in comparison to those of RP1. Small-amplitude oscillatory shear frequency sweep experiments were performed at temperatures that ranged from 20 °C to 50 °C to map elastic and damping contributions in the linear elastic regime. Large amplitude oscillatory shear (LAOS) experiments were conducted in the non-linear region and the material response was analyzed in the form of Lissajous curve representations with the values of perfect plastic dissipation ratio reported to identify the degree of plasticity. The results show that the SCBM exhibits dynamic properties that are similar in magnitude to those of temperature-conditioned RP1, but with minimal temperature sensitivity and weaker frequency dependence than RP1. Both SCBM and RP1 are identified as elastoviscoplastic materials, which is particularly important for accurate determination of backface signature in body armor evaluation. The mechanical properties of SCBM show some degree of aging and work history effects. The results from this work demonstrate that the rheological properties of SCBM, at small and large strains, are similar to RP1 with substantial improvements in BWM performance requirements in terms of temperature sensitivity and thixotropy.

scholarly journals Influence of ceramic properties on the ballistic performance of the hybrid ceramic–multi-layered UHMWPE composite armour

2020 ◽  
Author(s):  
Marzena Fejdyś ◽  
Katarzyna Kośla ◽  
Agnieszka Kucharska-Jastrząbek ◽  
Marcin Łandwijt
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Acoustic Impedance ◽  
Young's Modulus ◽  
Testing System ◽  
Ceramic Tiles ◽  
Ballistic Performance ◽  
Ballistic Resistance ◽  
Hybrid Ceramic ◽  
Uhmwpe Composite

Abstract The present research involves studies of the influence of the physico-mechanical properties of the ceramics on the ballistic resistance of the new concept of the hybrid, ceramic–multi-layered UHMWPE composite armour developed using SiC and Al2O3 ceramics differing in thickness. Ballistic verification of new design of the ballistic composite armour was conducted in the scope of the protection against more than one shot (multi-hit) using 7.62 × 39 mm MSC and 5.56 × 45 mm SS109 ammunition. Tests of physico-mechanical properties, covering the determination of density, acoustic impedance, Young’s modulus, hardness, and resistance to brittle fracture, were conducted for the ceramic materials. Obtained results show that the ballistic behaviour of the testing system based on ceramic tiles being made of the same materials (SiC or Al2O3) of the different thicknesses does not directly correlate with the hardness, brittle fracturing, or Young’s modulus of ceramics. For ceramic plates of the same thickness being made of different materials in chemical terms, performed studies have shown that the ballistic resistance of the testing system does not only depend on acoustic impedance of ceramic plates, which should be as similar as possible to the acoustic impedance of the backing material in the ballistic armour, but also the resistance to brittle fracturing K1c is an important parameter of the ceramic plates entering the composition of the armour, and it should be as high as possible. Only the combination of these two properties yields the best ballistic protection of the armour when testing using the multi-hit procedure with the use of 7.62 × 39 mm MSC and 5.56 × 45 mm SS 109 ammunition.

scholarly journals Estimating the Live Body Weight of American Black Bears in Florida

2016 ◽  
Vol 8 (1) ◽  
pp. 234-239 ◽  
Author(s):  
Tad M. Bartareau
Keyword(s):  
Body Weight ◽  
Confidence Interval ◽  
The Body ◽  
Black Bears ◽  
Reduced Model ◽  
Theoretic Approach ◽  
Validation Data ◽  
Data Set ◽  
Body Weight Data ◽  
Live Body Weight

Abstract Measuring the live body weight of large-bodied animals can be impractical when equipment needed to weigh individuals is inadequate or unavailable. My objective here was to develop a model to accurately estimate the live body weight of black bears Ursus americanus floridanus in Florida based on the relationship between scale weight and sex, morphometric measurements, and age predictor variables obtainable in the field. I used an information-theoretic approach to evaluate simple and multiple linear regression models with 70% of the data, and evaluated the best model in the set using the remaining 30%. A sex-specific model was sustained because the intercept and coefficient of age variable in female and male modeled relationships differed significantly. Chest girth2 was the best single predictor of body weight in each sex. A model including age, age2, and body length variables was better supported than chest girth2 alone. I also created a reduced model to estimate body weight when personnel may not have an opportunity to determine a bear's age. Even though there was decreasing support for the reduced model, differences between the observed and estimated body weight of all models applied to the validation data set were not significant. The 95% confidence interval on the bias of the best model ranged from −1.9 to 1.6 kg in females and −1.4 to 2.1 kg in males. The 95% confidence interval of the reduced model ranged from −1.8 to 2.3 kg in females and −2.5 to 0.5 kg in males. The body weight estimation models can be used to provide more live body weight data from handled black bears in Florida that are not weighed with a scale.

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