Effects of nanomaterials and particles on mechanical properties and fracture toughness of composite materials: a short review

The positive influence of nanomaterials and particles on the behavior of composite material structures have been studied which include the material structural characteristics, manufacturing process, compatibility with the other phases, size, dispersion process, adhesion, etc. The review on the choice of nanomaterials for a specific application and their effects on the bulk materials related to loadings have been overlooked. Thus, this paper reviewed the effects of nanomaterials based on loading conditions, sizes adhesions for the specific category of fillers. It also showed the appropriate filler amount for the enhancement of mechanical properties (i.e. stiffness and strength) and fracture toughness for both interlaminar and intralaminar perspectives. Furthermore, the effects of soft, hard and hybrid fillers were organized to put in evidence how some filler have magnificent effects for specific property enhancements. Moreover, the optimum nanomaterials application related to loading conditions were articulated in order to give a quick suggestion to the structural design engineers and researchers. Finally, the review gives a hint on how the addition of nanofillers and particle affects damage initiations and behavior of fiber reinforced plastic composites

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

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

Experimental and FEM analysis of three carbon steel characterization under quasi-static strain rate for bumper beam application

This paper investigates the mechanical behavior of three selected steel materials which are considered to be the bulk material of front most bumper beam of a vehicle that is suddenly loaded in the quasi-static range. Thirty-six constant strain rate uniaxial tension tests were performed. The test was performed on a HUALONG electro-hydraulic universal testing machine at four strain rates (3.33 × 10-3,3.33 × 10-2, 3.33 × 10-1, 3. 33s-1). The FEM which is ABAQUS/CAE is used to simulate the bumper subsystem using the three selected steel. The outcome shows that ultimate tensile strength (UTS) increase with an increase in strain rate and high alloy steel (HAS) material has the maximum mean UTS. The FEM in the post -processing stage gives the minimum displacement and maximum strain energy for HAS material when compared to the other two materials. Finally, from both experimental and ABAQUS explicit analysis the result shows HAS material is better suit for the bumper beam application

Implementation of Composites and Plastics Materials for Vehicle Lightweight

Due to ever more severe environmental regulations, safety standards and rise of fuel cost, design of lightweight vehicle is becoming a challenging task in automotive industry. For these reasons, multidisciplinary design approaches are becoming mandatory that takes into account all parties' interests. The thesis addresses the potential use of composites, nanomodified composites, thermoplastic and smart hot melts adhesives materials in selected automotive applications to achieve lightweight vehicle. Special attention was paid to specific parts of vehicle structures that are directly related to occupant and pedestrian safety concerns such as B-pillar, frontal bumper subsystem, and engine subframe. Two approaches were implemented to design composites and thermoplastic intensive vehicle components: experimental test and numerical simulation approaches. In experimental approach, experimental method was developed to establish reliable test procedure to characterize composite materials. Then, selected materials were manufactured and characterized under quasi-static and dynamic loading conditions. Furthermore, selected nano-modified composite materials were characterized to understand effect of presence of nano-clays into the matrix on the mechanical behavior of base material. On the other hand, thermoplastic material was modified with short glass fibers to improve its mechanical behavior for frontal vehicle system application. Besides, in this thesis adhesive joint was considered as alternative solution to achieve vehicle lightweight targets. Detailed material characterization and parametric study of hot melt adhesive (HMA) single lap joint were performed for bumper subsystem application. Accelerated ageing were also performed on selected HMA to represent the worst environmental condition in which the bumper subsystem could be exposed. Also, selected hot-melt adhesive was modified by nano-metal particles to obtain smart adhesive that allows bonded vehicle components to be easily detached during disassembly process. Particularly, simplified form of composite B-pillar (T-joint) was manufactured and quasi- static experimental tests were performed to validate the results obtained from numerical simulations. In numerical approach, composite and thermoplastic vehicle components were modeled, they are presented in chapters from seven to nine. Commercially available software have been used for these simulations. Structural analysis and optimizations were performed to obtain a competitive performance in terms of strength, stiffness and crash worthiness against conventional material solutions. The results found from experimental and numerical simulation works revealed that composites and thermoplastics materials can deliver better performances under static and crashing load conditions. Using those materials, considerable amount of vehicle weight reduction was also achieved by keeping the desired design performance criteria. It is also worth to underline that manufacturing process and joining techniques are some of the main factors that should be taken into consideration during design of composite and thermoplastic components for vehicle application

Design of a composite engine support sub-frame to achieve lightweight vehicles

The main objective of this paper is to analyze the possibility of the replacement of the engine sub-frame, which at present is made of steel or in some advanced cases in lightweight metals, with a new component made of Carbon/Epoxy composite material. A methodology is developed that helps to point out and solve the existing major problems with respect to the use of composite structures, by taking advantage from composite features such as the effect of variation of stacking sequence, ply angles, and stiffeners on load carrying capacity and stiffness of engine sub-frame. Furthermore, detailed numerical analysis has been performed to determine the natural frequencies and modes shapes of the proposed solutions. Results show competitive performance (with particular attention to the equivalent stiffness and natural frequency) of the new proposed solution based on composite material with respect to thereference steel sub-frame solution

The Effect of Nano Fillers on the Polymerization Shrinkage Kinetics and Mechanical Behavior of Composites

The main objective of the present study was to investigate the effect of nanoclay reinforcement on time-dependent volumetric shrinkage of three epoxy resins during polymerization and associated change of mechanical properties of the resulting composite materials. The materials used in this work were two part epoxies from Applied Poleramics Inc., namely, ER3/EH103, ER10/EH103, and DR5/EH103. Conventional methods which utilize 1D and 2D strains measurement are highly dependent on boundary conditions and can be used only for approximation of volumetric measurements. In order to measure the volume directly and monitor time-dependent shrinkage during the polymerization process, the Accupyc II 1340 gas pycnometer with Peltier controller was used. The materials were cured in-situ in the pycnometer chamber at 49 °C for 4 h followed by a post cure of 4 h at 65 °C. Time-dependent shrinkage of individual resins was monitored through continuous volumetric measurements during the entire curing cycle. On the other hand, the tensile specimens were cured in the conventional oven using the same curing cycle. Experimental results showed that depending on the epoxy and nanoclay concentration, variation in time-dependent shrinkage was observed relative to pristine epoxies. Besides, inclusion of nanoclay has shown considerable change in mechanical properties of the composite material. Although such observations were expected, detailed quantification on the volumetric shrinkage with a new technique and its effect on structural components made of such resin are not well documented. Overall, the study lays the groundwork for understanding shrinkage induced effects on strengths of resin/adhesive dominant structural components

Implementation of Composite and Recyclable Thermoplastic Materials for Automotive Bumper Subsystem

In order not only to meet the current targets in terms of safety, but also in terms of lightweight that means lower polluting gas emissions and fuel consumption, for a newly developed vehicle it is necessary to perform a number of component based tests. This kind of experimental tests is time consuming and very expensive. Therefore, it is recommended to develop cost effective design methodology and analysis using existing finite element methods in order to evaluate the performance of different design solutions under various loading, material and environmental conditions, since from the earliest stages of the design activity. This paper intends to address such design aspects and method of analysis with particular reference to the application of composite and recyclable thermoplastic materials to automotive front bumper design. Major constraints that have been dealt with are bumper crash resistance, absorbed energy and stiffness with particular reference to the existing bumper standards. Finally, the results predicted by the finite element analysis are evaluated and interpreted to insight the effectiveness of the proposed solution

Crashworthiness Analysis of Short Fiber Reinforced Composite Bumper Beam Using Multiscale Modeling and FE Simulation

In this work the crashworthiness response of a vehicle bumper beam made of short glass fiber reinforced composite was mainly investigated using multiscale material model and explicit time integration numerical technique. The matrix of the short glass fiber reinforced composite adopted for the bumper beam was a polyamide, i.e. a thermoplastic resin. Materials characterization was executed according to ASTM test procedures to verify the suitability of the material model and obtain the required characteristic data for FE model. For comparison purpose, reference material, steel, and CFRP were considered for FE simulations. FEM results showed that, based on equal bending stiffness criterion, the 30% glass polyamide based bumper beam exhibited the highest deceleration and least crashworthiness performance compared to the steel and CFRP bumper beams. On the other hand, result shows that CFRP composite beam has comparative performance with better energy absorption, weight saving, and gives reduced peak deceleration