16-08-2012, 02:09 PM
Effect of natural long fiber in thermoplastics for Automotive Structures
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Abstract
Bio polymers have more advantages compare to the ordinary polymers. in automotive components the usage of natural fibers increased to reduce the weight and increase the strength so that the fuel efficiency increases with out sacrificing safety of the structural components.. Designing the structures with the focus on improvement aspects is very important in the automotive industry. The goals are to increase the performance of the beams and also to find the solution to reduce the cost of beams hence able to reduce the production cost. The latest thermo plastic developments have resulted in higher material properties and more possibilities in the design of structural beams. However the use of steel, Aluminium, Glass mat thermoplastics (GMT), sheet metal components (SMC) structures becomes at higher cost than long fiber reinforced thermoplastics. This research is focused on partially eco- friendly hybrid long fiber reinforced thermo plastics with natural kenaf fiber to enhance the desired mechanical properties for automotive structural components.
Introduction
In Automotive sector the interest in natural fiber reinforced composites is growing rapidly due to their high performance in terms of mechanical properties, low cost, processing advantages and low density. The availability of Natural fibers such as kenaf have some advantages over traditional Reinforcement materials such as glass fiber in terms of cost, density, renewability,Recyclability, abrasiveness and biodegradability. The efficiency of the fiber reinforced composites depends on the fiber matrix interface and the ability to transfer stress from the matrix to the fiber. Natural fiber composites such as kenaf and polypropylene have already been applied in automotive parts [1]. The efficiency of the fiber reinforced composites depends on the fiber matrix interface and the ability to transfer stress from the matrix to the fiber. The advantages of natural fibers over traditional reinforcing materials such as glass fibers and mica are low density, low cost, are environmentally harmless and have good mechanical properties.
TENSILE TEST
The tensile test were performed according to the ASTM D3039 standard five set of specimens with recommended dimensions are created and tested by a calibrated AUTOGRAPH –AGS- 2003 testing machine with speed 5 mm/min. Five set of specimens with three different reinforcements were used for testing and the readings were plotted in fig (5).The tensile strength and the young’s modulus of the TKLFRT specimens were higher than common bumper beam materials such as LFRT .the KLFRT material also higher than the LFRT. Tensile modules of TKLFRT show dramatic property improvement with LFRT.Under a tensile load, the improved adhesion at fiber/matrix interface results in a more efficient stress transfer from the matrix to the reinforced fibers.
IMPACT TEST
Isod impact test methods were conducted according to the ASTMD256-
standard . Six samples with specified dimensions and defined notches were prepared and
the results were compared with LFRT material (Fig (6)). The density of the hybrid is
slightly higher than LFRT materials.while comparing the izod test results its proven that
KLFRT having challenging strength to LFRT.Impact strength of the KLFRT has to be
improved considerably to compete with LFRT,Though the poor impact strength of
KLFRT restricts their use in structural applications were high Impact strength is required,
they can replace engineering plastics in applications where tensile and flexural properties
are important than the impact strength.
CONCLUSIONS
This study focused on the mechanical properties of a hybrid kenaf/glass reinforced composites for utilization in passenger car bumper beam. A twisted kenaf hybrid material, which is fabricated by hot impregnation method present a good mechanical properties. The comparison charts shows some mechanical advantages compare to LFRT bumper beam material. This implies that a hybrid kenaf/glass reinforced material could be utilized in automotive structural components such as bumper beams and front end modules. More over impact properties could be improved by optimizing the structural parameters like thickness, beam curvature, and strengthening ribs.