Head Impact Injury Mitigation to Vehicle Occupants: An Investigation of Interior Padding and Head Form Modeling Options against Vehicle Crash

Traumatic Brain Injuries (TBI) occur approximately 1.7 million times each year in the U.S., with motor vehicle crashes as the second leading cause of TBI-related hospitalizations, and the first leading cause of TBI-related deaths among specific age groups. Several studies have been conducted to better understand the impact on the brain in vehicle crash scenarios. However, the complexity of the head is challenging to replicate numerically the head response during vehicle crash and the resulting traumatic Brain Injury. Hence, this study aims to investigate the effect of vehicle structural padding and head form modeling representation on the head response and the resulting causation and Traumatic Brain Injury (TBI). In this study, a simplified and complex head forms with various geometries and materials including the skull, cerebrospinal fluid (CSF), neck, and muscle were considered to better understand and predict the behavior of each part and their effect on the response of the brain during an impact scenario. The effect of padding thickness was also considered to further analyze the interaction of vehicle structure and the head response. The numeral results revealed that the responses of the head skull and the brain under impact load were highly influenced by the padding thickness, head skull material modeling and assumptions, and neck compliance. Generally, the current work could be considered an alternative insight to understand the correlation between vehicle structural padding, head forms, and materials modeling techniques, and TBI resulted from a vehicle crash

Investigation of influence of tab types on tensile strength of E-glass/epoxy fiber reinforced composite materials

Abstract Mechanical response of E-glass/epoxy fiber reinforced composite was investigated in tensile loading. Different types of tabs were considered in order to evaluate their effects on the tensile strength of material. Specifically, two types of molded tabs and five types of bonded tabs were considered in the study. The influence of different amount of gripping pressures on failure mode and on tensile strength of specimens was also considered in the analysis. The experimental results showed that the tabs configuration affected the tensile strength of the specimens. Starting from the experimental results, an appropriate testing methodology is proposed for E-glass/epoxy fiber reinforced composite specimens in order to reduce problems that may arise during the test and to optimize procedures for preparation of specimens

Nano-additives and their effects on the microwave absorptions and mechanical properties of the composite materials

The review addresses the effect of various carbon and iron-based percentage nano- additives on both electromagnetic (EM) wave and mechanical properties of composite materials. It also assessed the influence of particle and fiber size along with the manufacturing process, on mechanical properties (tensile strength and flexural strength), fracture behaviors (fracture toughness) and electromagnetic properties (reflection loss). Reviewing the selection of nanomaterials for a particular frequency band and application, as well as their impacts on bulk materials in relation to loading, were overviewed. As per this review, adding those iron and carbon-based additives influence positively for both electromagnetic and mechanical properties. Furthermore, review organized natural based fiber and filler-based composites along with fillers for the production of green strong radar materials. The review also showed, how highest and smaller percentage of iron-based fillers affected for microwave absorption and mechanical properties. Mainly, the optimized use of nano particles percentage for both mechanical and electromagnetic wave to produce strong radar materials were overlooked. Finally, these papers give a quick hint on how these nano particles manufacturing methods and particle size affect the mechanical properties and micro wave absorption of composite materials

Effect of Hybrid (Micro- and Nano-) Fillers on Impact Response of GFRP Composite

The impact behavior of hybrid nano-/micro-modified composite was investigated in Glass Fiber Reinforced Plastics (GFRP). The hybrid nano-/micro fillers chosen were Cloisite 30B nanoclay and 3MTM Glass Bubbles iM16K. Impact testing at varying energy levels was performed using drop weight impact tests (DWIT). The impact response was evaluated in terms of damage progression by visual observations, evolution of the peak force and stiffness with corresponding absorbed energy. At high impact energy levels, pristine and Glass Bubble modified laminates showed the highest peak force and low absorbed energy with penetration of the impactor through their thickness, while nanoclay-modified laminate showed the highest absorbed energy and minimum peak reaction force without penetration. The hybrid laminate exhibited intermediate absorbed energy and peak reaction force sustained for longer time. Overall, the work demonstrated the ability to tailor composite properties for enhancement of impact performance by using various types, concentrations and configuration of nano/micro particles

Effects of Cloisite nanoparticles on interlaminar fracture toughness and resistance curve of S-glass fiber reinforced polymer composite

The effect of particular nanoclay, Cloisite 20B, addition on the interlaminar fracture toughness of a plain-woven type glass fiber reinforced plastic (GFRP) composite was experimentally investigated. The mode-I tests were conducted based on a double cantilever beam (DCB) test. Results showed that the inclusion of nanoclays improved the interlaminar fracture toughness of the GFRP composite in the range of 12.65% and 54.07% as compared with the pristine one, with a progressive increment of the nanoclays weight content (from 0.5 to 2%). A better understanding of Cloisite 20B filler's contribution to improving the delamination resistance can lead to a design of better melt flow rate and good elongation at break structural composites

High resolution imaging of impacted CFRP composites with a fiber-optic laser-ultrasound scanner

Damage induced in polymer composites by various impacts must be evaluated to predict a component’s post-impact strength and residual lifetime, especially when impacts occur in structures related to human safety (in aircraft, for example). X-ray tomography is the conventional standard to study an internal structure with high resolution. However, it is of little use when the impacted area cannot be extracted from a structure. In addition, X-ray tomography is expensive and time-consuming. Recently, we have demonstrated that a kHz-rate laser-ultrasound (LU) scanner is very efficient both for locating large defects and evaluating the material structure. Here, we show that high-quality images of damage produced by the LU scanner in impacted carbon-fiber reinforced polymer (CFRP) composites are similar to those produced by X-ray tomograms; but they can be obtained with only single-sided access to the object under study. Potentially, the LU method can be applied to large components in-situ