Low Velocity Impact Behavior of Glass Filled Fiber-Reinforced Thermoplastic Engine Components
This paper concerns automotive parts located underneath the engine and in particular the engine oil pan. Classically made of stamped steel or cast aluminum, new developments have allowed the manufacture oil pans with polyamide 66 reinforced by 35% weight of short glass fiber. However, polyamides have some limitations and the most significant is their response to localized impact loading. The nature of the impact considered here is of a typical stone collected from the road and projected into the oil pan. Low velocity impact investigations were carried out using a gas gun and drop weight tower. The study shows that the design of the oil pan has a significant contribution in the shock absorption. In addition to the material properties, the geometry and the ribbing both cleverly combined, increase the impact resistance of the component significantly. Areas of oil pan design improvement have been identified and conclusions drawn.
Low velocity impact performance of recyclable all-polypropylene composites
Abstract Highly oriented polypropylene (PP) tapes, with high tensile strength and stiffness achieved by molecular orientation during solid state drawing are consolidated to create high performance recyclable “all-polypropylene” (all-PP) composites. These composites possess a large temperature processing window (>30 °C) and a high volume fraction of highly oriented PP (>90%). This large processing window is achieved by using co-extruded, highly drawn PP tapes. This paper investigates the impact resistance of these all-PP composites, and the relationship between penetrative and non-penetrative impact behaviour, and composite consolidation conditions. The response of all-PP composites to falling weight impact is reported together with a comparison to conventional commercial glass reinforced polypropylene composites. A model for energy absorption is proposed by comparison with previous studies based on interfacial and tensile failure of tapes and composites.
Analysis of zone-drawing process in preoriented polypropylene
Preoriented isotactic polypropylene was used to clarify the molecular process in zone-drawing with which the necking part is confined in a thin heating zone during uniaxial drawing. The process was analyzed on the basis of rate process, the mechanical properties of zone-drawn samples, and the superstructural change during zone-drawing. The values of activation energy for deformation, ΔH*, and the activation volume, ΔV*, were affected by the deformation mechanisms preferentially taking place during the zone-drawing. The attainable maximum modulus of zone-drawn sample at θ = 45° was larger than those at θ = 0° and 90°. The highest strength was also obtained at θ = 45°. The values of modulus and strength strongly depended on both the orientation function of the crystal c-axis and the orientation function of amorphous chains. In the region of a very high zone-drawing rate, in which microcracks are preferentially formed, both modulus and strength decreased, whereas they increased with increasing the zone-drawing rate below this region, giving the optimum condition for achieving the maxima in the modulus and strength.