Abstract

Glass fibers were used to investigate the impact of loose fiber reinforcement on the performance characteristics of"br" asphalt mixtures. For the laboratory tests on asphalt mixes a fiber content of 0.5 mass.-% was chosen. This paper"br" presents selected results of fatigue, stiffness (both cyclic indirect tensile tests) and rutting / plastic deformation"br" tests (cyclic uniaxial compression test) on different asphalt mixes. An asphalt base course mix AC 22 T S, an"br" asphalt binder course mix AC 16 B S and an asphalt concrete AC 8 D S were chosen to determine the effect of"br" glass fiber reinforcement. Furthermore, the fiber length was varied for the AC 16 B S. The content of reclaimed"br" asphalt (RA) was varied for the AC 22 T S. Depending on the mix design the bitumen content was increased up"br" to 0.3 mass.-%.

Abstract

EuroNCAP tests are carried out since 1997. The test procedure in general is comparable to the EC Directive 96/79 with a test speed of 64 km/h. This increased test speed implies a higher frontal stiffness for new vehicle designs in order to achieve a high ranking. This frontal stiffness is one of the major factors for compatibility in car to car collisions. To support the European 4th framework compatibility research activity, load cell barriers are used in ENCAP tests carried out at the TNO Crash Safety Centre and TRL. In this paper global force displacement characteristics of a number of different vehicle classes are compared and analysed. It will be made clear that small vehicles in the past known not to be strong can produce comparable force levels as large cars. For compatibility this means that in small car against large car collisions the small car's passenger compartment can stay stable and can offer better protection to the occupants, since from accident analyses it is known that serious injury often is caused by high intrusion into the passenger compartment. For frontal impacts this means that ENCAP tests have driven small cars to increased compatibility for one aspect of compatibility (cabin integrety) at higher speed. MPV's with high masses and little crushable space show more aggressive force displacement characteristics. This car category is expected to behave less compatible hitting small cars or medium size passenger cars. A longer crushable space for this category is desired, which is in conflict with the special look for these vehicles. This trend in stiffer vehicle fronts might result in future modifications of the European side impact barrier, which is currently based on average vehicle fronts of old vehicles. This item is only mentioned and will not be further discussed

Abstract

At the state of art, current simulative methods modelling joint properties as fixed interaction between components or concentrate on the characterization of the joint stiffness and damping of coupled metallic structures. In the current work, the developed thin layer interaction (TLI) method was applied to study the influence of the joint stiffness and damping of plastic components coupled with metallic structures. The joint stiffness and damping of different coupled metallic-plastic joint structures was characterized experimentally and was used to fill the reduced transverse shear stiffness and damping tensors of the numerical TLI model. The TLI model was used to determine the structural dynamics behavior of a short glass fiber reinforced plastic engine bracket mounted to a steel block. The comparison of experimental and simulative results shows a better correlation under the usage of the TLI model compared to a fixed modeled joint behavior. As result, the TLI model allows a better prediction of the structural dynamics of coupled plastic components. Further researches focus on the accurate experimental estimation of the boundary conditions regarding excitation and mounting of the plastic components. Thus, a more realistic modelling of the numerical joint boundary conditions is possible for an improved simulation of the structural dynamics of plastic components.