21 research outputs found

    Implementation of Composites and Plastics Materials for Vehicle Lightweight

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    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

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    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

    Structural Weight and Stiffness Optimization of a Midibus Using the Reinforcement and Response Surface Optimization (RSO) Method in Static Condition

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    Midibuses are medium-sized buses widely used for transportation purposes in Asia and Africa. However, most midibuses are locally built and indirectly regulated through inspecting the end product (finished bus) during licensing for the public transport business in Ethiopia. Due to lack of engineering analysis and testing, low stiffness and overweight of midibus were compromised. This research was aimed at analyzing and optimizing the midibus structure using the reinforcement and response surface optimization (RSO) method for pure bending and torsion loading cases. Results show that the maximum deformation occurred at the roof section of the original structure during both loading cases. Furthermore, the reinforcement design was found by replacing the cross section and layouts of structural members and adding reinforcements for the most suitable location of the original structure. Response surface optimization with the multiobjective genetic algorithm (MOGA) method in ANSYS DesignXplorer was performed on the reinforced structure to maximize the bending and torsional stiffness with reduced weight. The bending stiffness of the reinforced and optimized structure increased by 41.65% (1911.4 N/m) and 10.02% (651.7 N/m), respectively. In addition, the torsional rigidity or stiffness of the bus structure was improved by 12.56% (173.31 Nm/deg) via reinforcement design. Moreover, the torsional stiffness of the optimized (RSO) model was increased by 3.29% (51.07 Nm/deg). Reinforcement design was effectively reduced by 5.23% of the structure’s weight. Moreover, the RSO method has also decreased the weight of the reinforced structure by 2.64%

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

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    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

    Implementation of Composite and Recyclable Thermoplastic Materials for Automotive Bumper Subsystem

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    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

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

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    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

    Evaluation of Progressive Damage of Micro-Glass Bubble Modified Composite Laminates Under Repeated Impacts

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    This conference proceeding was published in Proceedings of the International Conference on Impact Loading of Structures and Materials

    Crashworthiness evaluation of composite vehicle side door

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    This paper intends to address the crashworthiness, design aspects, and method of analysis with particular reference to the application of composite materials to automotive front door design. The current material solution, steel solution, has been substituted by chosen composite materials on the bases of equal thickness and equal stiffness criteria. Major constraints are dealt with crash resistance and stiffness of door panels and impact beam against side crash, according to exist standards. Finally, the results predicted by the finite element analysis are evaluated and interpreted on the bases of crashworthiness and method of production to insight the effectiveness of the proposed solution. The results revealed that composite door could be better for absorbing energy during the side crash impact if it is designed properl
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