Analysis On The Performance Of Long Glass Fiber Reinforced Polypropylene Composites And Its Application In Car Body

Light weight is one of the key technologies to solve automobile energy consumption and environmental pollution,which is of great significance to the sustainable development of automobile industry.Long glass fiber reinforced polypropylene(LGF/PP)composites is widely used in autoindustry for its good combination property,design-ability,performance-price ratio and recyclability.In this thesis,the material composition and process parameters used for the preparation of certain kind of car bottom plate can be determined by the choice of materials,preparation,molding and performance.The feasibility of related parameters in practical application is verified,and the systematic approach and process is established.Detailed contents are listed as follows:(1)Analysis of material composition and preparation process on mechanical properties.The effects of material composition and preparation parameters on the mechanical properties of LGF/PP composites are investigated and the better mechanical properties are obtained.This thesis expounds the preparation of LGF/PP composites by airlaid process and the working principle of the key parts of production equipment.LGF/PP mixed mats with different glass fiber mass fraction and material density are prepared by airflow process,and the good material composition is optimized by using the tensile strength and flexural strength as the evaluation indexes.(2)Analyze the influence of forming thickness and foaming degree on the tensile and sound absorption properties of the material.Measure the tensile strength and elastic modulus when the thickness of the material ranges from 1mm to 8mm.The microscopic characteristics of different thickness samples are observed by scanning electron microscope,and the mechanism and regularity of LGF/PP composites are analyzed.Analyze the relationship between the whole sound absorption performance of the material in the high and low frequency region through the sound absorption test.Finally,we can achieve to the optimized value of the forming thickness through mechanical properties and sound absorption performance.(3)Molding and loading validation of LGF/PP composites.The characteristics of the molding process are analyzed and the technological process is worked out,and the molding process parameters are determined.According to the material composition and forming thickness obtained in the previous sections,the car bottom shield is prepared by the molding process,then the common defects of the molding are analyzed and the corresponding measures are put forward.Finally,the loading test is carried out.