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.

Rheological Characterization of Body Lotions

2001 ◽  
Vol 11 (2) ◽  
pp. 83-88 ◽  
Author(s):  
Ming Long Yao ◽  
Jayesh C. Patel
Keyword(s):  
Thermal Stability ◽  
Temperature Sensitivity ◽  
Viscoelastic Properties ◽  
Rheological Characterization ◽  
Performance Properties ◽  
Rheological Measurements ◽  
End Use ◽  
And Storage

Abstract This study is attempted to demonstrate the application of rheological measurements in characterization of cosmetics products. As part of this study, several rheological tests were carried out on three common, commercially available body lotions to analyze their complex properties. The tests described in this study were simple and predictive in which the viscoelastic properties were successfully related with the end-use performance properties such as applicability, processing behavior, temperature sensitivity and storage and thermal stability.

scholarly journals Rheological Characterization of Alginate Based Hydrogels for Tissue Engineering

MRS Advances ◽  
2017 ◽  
Vol 2 (24) ◽  
pp. 1309-1314 ◽  
Author(s):  
Pengfei Duan ◽  
Nehir Kandemir ◽  
Jiajun Wang ◽  
Jinju Chen
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Tissue Engineering ◽  
Drug Delivery Systems ◽  
Rheological Characteristics ◽  
Scaffold Material ◽  
Rheological Characterization ◽  
Frequency Sweep ◽  
Strain Sweep

ABSTRACTHydrogels have been widely used in many applications from tissue engineering to drug delivery systems. For both tissue engineering and drug delivery, the mechanical properties are important because they would affect cell-materials interactions and injectability of drugs encapsulated in hydrogel carriers. Therefore, it is important to study the mechanical properties of these hydrogels, particularly at physiological temperature (37°C). This study adopted strain sweep and frequency sweep rotational rheological tests to investigate the rheological characteristics of various tissue engineering relevant hydrogels with different concentrations at 37°C. These hydrogels include alginate, RGD-alginate, and copolymerized collagen/alginate/fibrin. It has revealed that the addition of RGD has negligible effect on the elastic modulus and viscosity of alginate. Alginate gels have demonstrated shear thinning behavior which indicates that they are suitable candidates as carriers for cells or drug delivery. The addition of collagen and fibrin would reinforce the mechanical properties of alginate which makes it a strong scaffold material.

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.

scholarly journals Processing of Sr2+ Containing Poly L-Lactic Acid-Based Hybrid Composites for Additive Manufacturing of Bone Scaffolds

2020 ◽  
Vol 7 ◽  
Author(s):  
Priscila Melo ◽  
Raasti Naseem ◽  
Ilaria Corvaglia ◽  
Giorgia Montalbano ◽  
Carlotta Pontremoli ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Additive Manufacturing ◽  
Hybrid Composites ◽  
Homogeneous Distribution ◽  
Fused Filament Fabrication ◽  
Rheological Characterization ◽  
Biodegradable Composite ◽  
Manufacturing Technologies

Biodegradable composite materials represent one of the major areas of investigation for bone tissue engineering due to their tuneable compositional and mechanical properties, which can potentially mimic those of bone and potentially avoid the removal of implants, mitigating the risks for the patient and reducing the overall clinical costs. In addition, the introduction of additive manufacturing technologies enables a strict control over the final morphological features of the scaffolds. In this scenario, the optimisation of 3D printable resorbable composites, made of biocompatible polymers and osteoinductive inorganic phases, offers the potential to produce a chemically and structurally biomimetic implant, which will resorb over time. The present work focuses on the development and process optimisation of two hybrid composite filaments, to be used as feedstock for the fused filament fabrication 3D printing process. A Poly L-lactic acid matrix was blended with either rod-like nano-hydroxyapatite (nano-HA) or nanoparticles of mesoporous bioactive glasses, both partially substituted with strontium (Sr2+), due to the well-known pro-osteogenic effect of this ion. Both inorganic phases were incorporated into Poly L-lactic acid using an innovative combination of processes, obtaining a homogeneous distribution throughout the polymer whilst preserving their ability to release Sr2+. The filament mechanical properties were not hindered after the incorporation of the inorganic phases, resulting in tensile strengths and moduli within the range of cancellous bone, 50 ± 10 MPa and 3 ± 1 GPa. Finally, the rheological characterization of the hybrid composites indicated a shear thinning behaviour, ideal for the processing with fused filament fabrication, proving the potential of these materials to be processed into 3D structures aiming bone regeneration.

Mechanical properties of PAN-based gel electrolytes: small-amplitude oscillatory shear study

2004 ◽  
Vol 33 (2-3) ◽  
pp. 125-129 ◽  
Author(s):  
I. Nicotera ◽  
C. Oliviero ◽  
L. Coppola ◽  
R. Gianferri ◽  
G.A. Ranieri
Keyword(s):  
Mechanical Properties ◽  
Small Amplitude ◽  
Oscillatory Shear ◽  
Small Amplitude Oscillatory Shear ◽  
Gel Electrolytes

Experimental Study of the Characterization of Ultra-High Molecular Weight Polyethylene Fiber Plastic

2013 ◽  
Vol 750-752 ◽  
pp. 840-844 ◽  
Author(s):  
Yao Ke Wen ◽  
Cheng Xu ◽  
Xue Hua Dong ◽  
Shu Wang
Keyword(s):  
Molecular Weight ◽  
Shear Strength ◽  
High Molecular Weight ◽  
Body Armor ◽  
Fiber Direction ◽  
Ballistic Performance ◽  
Uhmwpe Fiber ◽  
Polyethylene Fiber ◽  
Ultra High Molecular Weight

Ultra-high molecular weight polyethylene (UHMWPE) fiber reinforced plastic (UFRP) is an integral part of hard body armor. The intensive study on the material characterization of UFRP can help to understanding the bulletproof mechanism and behind-armor blunt trauma (BABT) well, and thus improve the performance of body armor. The research presented in this paper represents an effort to characterize the properties of UFRP under quasi-static and ballistic loading. The tensile behavior along the fiber direction and through thickness compressive behavior were obtained using an universal material testing machine. Experiments show that the tensile strength and compressive strength of UFRP are approximately 500MPa and 650MPa, respectively. The through thickness shear strength of UFRP was also obtained according to the punch-shear testing, and a set of special clamp was used to clamp the samples. The composite has been found to have a low shear strength. The UFRP was impacted by a 4.8mm diameter spherical fragment with velocity 694m/s~920m/s, to study the ballistic performance. And the height and radius of the deformed conical region on the back face of UFRP were captured using high-speed photography technique. Results show the maximum transient height of the cone is about 3 to 4 times greater than the final height of the cone, and the radius of the cone reaches to 59±7.4mm. The ballistic limit of the 11mm thick UFRP is approximately 800m/s.

Rheological Enhancement of Artificial Sputum Medium

2020 ◽  
Vol 30 (1) ◽  
pp. 27-38
Author(s):  
Mingyang Tan ◽  
Yating Mao ◽  
Travis W. Walker
Keyword(s):  
Mechanical Properties ◽  
Cystic Fibrosis ◽  
Rheological Properties ◽  
Hierarchical Structure ◽  
Particle Transport ◽  
Xanthan Gum ◽  
Rheological Characterization ◽  
Diffusive Behavior ◽  
Long Timescales

AbstractThis investigation proposes a synthetic biofluid, artificial sputum medium (ASM) and xanthan gum (XG), that mimics the mucus from a patient with cystic fibrosis, and investigates the rheological properties both macroscopically and microscopically. Macroscopic rheological characterization cannot address the heterogeneity or the behavior of particle transport inside the mucus. Microscopic rheology enables the characterization of the microenvironment by using microparticles as probes.The addition of XG to ASM provides a tunable parameter that enables the mechanical properties to be consistent with real mucus. Particles that were suspended in a media of ASM with XG displayed a subdiffusive behavior at short timescales with a diffusive exponent that decreases with an increase in concentration of XG. At long timescales, particles that were suspended in ASM+XG with a concentration of XG of 0.1% to 0.4% displayed diffusive behavior. While in more concentrated samples (0.5% and 1.0%), the particles were constrained inside local elastic “cages”. The microscopic moduli that were calculated showed consistently lower moduli than rotational rheometry. This discrepancy suggests that the solutions of XG have a hierarchical structure that better represents the weakly associated microstructure of mucus that is found in real sputum.

Rheological characterization of biocompatible associative polymer hydrogels with crystalline and amorphous endblocks

2006 ◽  
Vol 21 (8) ◽  
pp. 2118-2125 ◽  
Author(s):  
Sarvesh K. Agrawal ◽  
Naomi Sanabria-DeLong ◽  
Gregory N. Tew ◽  
Surita R. Bhatia
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Elastic Modulus ◽  
Block Length ◽  
Rheological Characterization ◽  
Precise Control ◽  
Order Of Magnitude ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

Control over mechanical properties of hydrogels is of primary importance for the use of these materials in drug delivery and tissue engineering applications. We demonstrate here that crystallinity and block length of poly(lactide) (PLA) can be used to tune the elastic modulus of associative network gels of poly(lactide)–poly(ethylene oxide)–poly(lactide) over several orders of magnitude. Polymers made with crystalline L lactic acid blocks formed very stiff hydrogels at 25 wt% concentration with an elastic modulus that was almost an order of magnitude higher than hydrogels of polymers with a similar molecular weight but containing amorphous D/L-lactic acid blocks. The relaxation behavior and crosslink density of gels are also significantly influenced by crystallinity of PLA and are again a function of PLA block length. Using these variables we can design new tailor-made materials for biomedical applications with precise control over their structure and mechanical properties.

Sign in / Sign up

Export Citation Format

Share Document