Development Of Fiber-Reinforced Epoxy Composite Energy Absorber For Automotive Bumper System

Bumper is an important safety component in a vehicle. Approximately 70% of damage claim occurred from low speed impact. In a number of European countries, pedestrians contribute 12-35% of the number of severely injured or killed victims of road traffic accidents. The bumper absorber plays an important role in energy absorption in automotive bumper system. There are two types of energy absorber in modern car. The first one is for low impact and another one for crashworthiness impact. In the case of low impact test energy absorption, it normally uses foam as an absorber which in some material cases is harmful and need more equipment for production also there are uncompleted recovery after compression. Fiber reinforced polymer composite material offers essential characteristics such as weight reduction, design and manufacturing flexibility and safety improvement. In this research the above-mentioned parameters and the inherent characteristics of fiber reinforced polymer composite material have been used in designing polymer composite parts as an energy absorber in automotive bumper system. In developing the reinforced polymer composite absorber the work of Neopolen_P (2006) and AISI (2004) were followed as guides with some modifications. A series of reinforced composite absorber was installed between fascia and beam in place of a series of expanded polypropylene (EPP) absorber as was used by Neopolen_P (2006). The finite element analysis and experimental work were carried out to investigate the effect of energy absorption analysis of the elliptical shape of the composite material. The simulation was performed using a commercially available finite element software package (LUSAS). It is found the ratio 150mm over 75 mm is suitable and the fiber orientation [0],[90] are the best among [0], [10], [20], [30], [40], [45], [50], [60], [70], [80], and [90] orientations. The experimental work had been carried out to examine the effects of composite elliptical absorber on energy absorption behavior subjected to quasi-static compressive load. The composite elliptical absorber was fabricated from E- glass and carbon fiber with the orientation of [0, 90], [0, 45,-45, 0] and [45, 0, 90]s. The load and accumulative energy versus displacement were tested under compressive quasistatic loading using the universal hydraulic testing machine (Instron 8500) and the results were finally compared with FEA results. It can be concluded that the composite absorber is useful in case of leg-form impact in car bumper and repeated compression recovery is better than expanded polypropylene (EPP) material and the equipment for manufacturing and number of parts are lower than EPP absorber. It can be used in different cars with various spaces by small changing in production equipment

Development of fiber reinforced epoxy composite energy absorber for automotive bumper system

The bumper absorber has the main task in energy absorption in automotive bumper system. There are two types of energy absorber in modern cars. The first one is for low impact as a reversible energy absorber and another one for crash worthiness impact as an irreversible energy absorber. In the case of low impact test energy absorption, it normally uses foam as an absorber which in some material cases is harmful and need more equipment for production; also there is incomplete recovery after compression. The fiber reinforced polymer composite material offers essential characteristics such as weight reduction, design and manufacturing flexibility and safety improvement. Elliptical shape absorber is a suitable geometry in energy absorption. Substitution of elliptical polymer composite material for foam material in car bumpers is discussed

Conceptual design of a polymer composite automotive bumper energy absorber

In this paper, a study of conceptual design of fibre reinforced epoxy composite bumper absorber is presented. This study describes the use of the composite in energy absorption in car bumper as a pedestrian energy absorber. The systematic exploitation of proven ideas or of experience was used to generate the ideas and the most suitable idea was followed as a guide for conceptual design. The absorber was analyzed experimentally and the data from these experiments were used to decide on the number of energy absorber to be used in the design. Final design of the composite energy absorber in elliptical shape with two slots at both ends was considered. The method of fixing the energy absorber to the fascia and bumper was also studied

Effect of the strengthened ribs in hybrid toughned kenaf/glass epoxy composites bumper beam

The growth of car production governs new environmental regulations “End-of Life Vehicles” (ELV) to enforce car manufacturer to substitute synthetic material to bio based materials. Low mechanical properties of natural fibre composite confine their application in automotive non-structural components. Hybridizations of kenaf with glass fibre along with epoxy PBT toughening did not completely fulfill the required impact property of the developed bio-composite bumper beam to substitute with typical material of the bumper beam glass mat thermoplastic (GMT). Therefore, in the first stage of the geometrical improvement “concept selection” concluded that the double hat profile (DHP) is the most suitable concept out of eight bumper beam concepts when six parameters with different weight are determined. In second trial, the usage of strengthen rib is employed to improve the impact property and performance of the bumper beam for utilization of hybrid kenaf/glass fibre as a car bumper beam

Mechanical properties of hybrid kenaf/glass reinforced epoxy composite for passenger car bumper beam

It is estimated that the annual world car production rate will reach 76 million vehicles per year by 2020. New regulations such as the EU End of Life Vehicles (ELV) regulations are forcing car manufacturers to consider the environmental impact of their production and possibly shift from the use of synthetic materials to the use of agro-based materials. Poor mechanical properties and certain manufacturing limitations currently limit the use of agro-based materials to non-structural and semi-structural automotive components. The hybridization of natural fiber with glass fiber provides a method to improve the mechanical properties over natural fibers alone. This research is focused on a hybrid of kenaf/glass fiber to enhance the desired mechanical properties for car bumper beams as automotive structural components with modified sheet molding compound (SMC). A specimen without any modifier is tested and compared with a typical bumper beam material called glass mat thermoplastic (GMT). The results indicate that some mechanical properties such as tensile strength, Young’s modulus, flexural strength and flexural modulus are similar to GMT, but impact strength is still low, and shows the potential for utilization of hybrid natural fiber in some car structural components such as bumper beams

Concept selection of car bumper beam with developed hybrid bio-composite material

Application of natural fibre composites is going to increase in different areas caused by environmental, technical and economic advantages. However, their low mechanical properties have limited their particular application in automotive structural components. Hybridizations with other reinforcements or matrices can improve mechanical properties of natural fibre composite. Moreover, geometric optimizations have a significant role in structural strength improvement. This study focused on selecting the best geometrical bumper beam concept to fulfill the safety parameters of the defined product design specification (PDS). The mechanical properties of developed hybrid composite material were considered in different bumper beam concepts with the same frontal curvature, thickness, and overall dimensions. The low-speed impact test was simulated under the same conditions in Abaqus V16R9 software. Six weighted criteria, which were deflection, strain energy, mass, cost, easy manufacturing, and the rib possibility were analyzed to form an evaluation matrix. Topsis method was employed to select the best concept. It is concluded that double hat profile (DHP) with defined material model can be used for bumper beam of a small car. In addition, selected concept can be strengthened by adding reinforced ribs or increasing the thickness of the bumper beam to comply with the defined PDS

Preliminary analysis of knee stress in Full Extension Landing

OBJECTIVE: This study provides an experimental and finite element analysis of knee-joint structure during extended-knee landing based on the extracted impact force, and it numerically identifies the contact pressure, stress distribution and possibility of bone-to-bone contact when a subject lands from a safe height. METHODS: The impact time and loads were measured via inverse dynamic analysis of free landing without knee flexion from three different heights (25, 50 and 75 cm), using five subjects with an average body mass index of 18.8. Three-dimensional data were developed from computed tomography scans and were reprocessed with modeling software before being imported and analyzed by finite element analysis software. The whole leg was considered to be a fixed middle-hinged structure, while impact loads were applied to the femur in an upward direction. RESULTS: Straight landing exerted an enormous amount of pressure on the knee joint as a result of the body's inability to utilize the lower extremity muscles, thereby maximizing the threat of injury when the load exceeds the height-safety threshold. CONCLUSIONS: The researchers conclude that extended-knee landing results in serious deformation of the meniscus and cartilage and increases the risk of bone-to-bone contact and serious knee injury when the load exceeds the threshold safety height. This risk is considerably greater than the risk of injury associated with walking downhill or flexion landing activities

Effect of polybutylene terephthalate (PBT) on impact property improvement of hybrid kenaf/glass epoxy composite.

Environmental regulations, costs and lightweight encourage car manufacturers to develop new reliable products. Epoxy provides a reliable fibre impregnation and creates substantial three-dimensional (3D) cross-linking for proper load transmission and impact strength improvement, but their low toughness decreases their energy absorption. Thermoplastic toughening improves the epoxy impact property with a low thermo-mechanical defect. This study, focused on improving the impact property of hybrid kenaf/glass fibre epoxy composite by use of a modified sheet moulding compound (GMT). The results indicated that most of the mechanical properties of developed material were almost the same as those of the GMT, except impact. This result highlights the potential for utilisation of the toughened hybrid bio-composite in some automotive structural components. Moreover, geometric parameters, e.g., cross-section, thickness, and reinforcement ribs suggest an improvement of structural impact resistance to comply with the bumper beam product design specification (PDS)

Physicochemical characterization of pulp and nanofibers from kenaf stem

The aim of this study was to isolate cellulose nanofibers from kenaf (Hibiscus cannabinus) stem using chemo-mechanical treatments. The fiber purification method included pulping and bleaching processes whereas the mechanical treatments employed to isolate kenaf nanofibers were grinding and high pressure homogenizing. Kenaf nanofibers were found to have diameters in the range of 15-80 nm while most nanofibers have diameters within the range 15-25 nm. Fourier transform infrared spectroscopy (FTIR) showed that the chemical treatments removed lignin and most of the hemicelluloses from the fibers. The thermal characteristics of the fibers were analyzed using the technique of thermogravimetric analysis (TGA) which demonstrated that these characteristics were enhanced noticeably both for the bleached pulp and nanofibers. On the other hand, the X-ray analysis indicated that both chemical and mechanical treatments can improve the crystallinity of fibers

Development process of new bumper beam for passenger car: a review.

Bumper beam absorbs the accidental kinetic energy by deflection in low-speed impact and by deformation in high-speed impact. The safety regulations “low-, and high-speed, and pedestrian impacts” along with new environmental restrictions “end-of-life vehicles” increased the complexity level of bumper system design. The new bumper design must be flexible enough to reduce the passenger and occupant injury and stay intact in low-speed impact besides being stiff enough to dissipate the kinetic energy in high-speed impact. The reinforcement beam plays a vital role in safety and it must be validated through finite-element analysis (FEA) and experimental tests before mass production. The careful design and analysis of bumper beam effective parameters can optimize the strength, reduce the weight, and increase the possibility of utilizing biodegradable and recyclable materials to reduce the environmental pollution. Developing the correct design and analysis procedures prevents design re-modification. On the other hand, analysis of the most effective parameters conducive to high bumper beam strength increases the efficiency of product development. Cross section, longitudinal curvature, fixing method, rib thickness, and strength are some of the significant design parameters in bumper beam production. This study critically reviews the related literature on bumper design to come up with the optimal bumper beam design process. It particularly focuses on the effective parameters in the design of bumper beam and their most suitable values or ranges of values. The results can help designers and researchers in performing functional analysis of the bumper beam determinant variables