Papers by Author: Mike Daniels

Abstract: Vehicle safety has increasingly become an economical factor for vehicle manufacturers and this has become most apparent in car safety [1-4]. Manufacturers are now spending considerable resources on safety research. Government requirements on safety have compelled manufacturers to carry out considerable number of crash tests to validate the safety of their cars [6-7]. The data from these tests is important in the development of simulation models employing finite element (FE) software. Many companies predict crashworthiness using commercially available software such as PAMCARSH and LS-DYNA. These simulations are based on mathematical constitutive equations and hence any simulation created is only as representative as the constitutive equations used. This project has studied the reliability of the material models used by LS-DYNA. Material models selected for analysis are used extensively by impact simulations software and were namely: Power Law Plasticity and Cowper/Symonds. Piecewise Linear Plasticity was also selected because it is based on a true stress/strain and is expected that the simulation would be representative. The models were developed using Belytschko-Lin-Tsay shell elements and were compared with experimental tests employing uni-axial tension strips carried out on three materials – aluminium, high strength steel and mild steel. The tests were carried out using a DARTEC tensile testing machine (up to strain rate of 2.0s-1) at UCE in Birmingham. Testing for the higher strain rates (aluminium up to 269.1s-1, mild steel up to 460s-1, and high strength steel up to 456.9s-1), were carried out at The Royal Military College, Shrivenham using a ROSAND tester.

Abstract: For reasons of cost and weight, light gauge sheet is used wherever possible for metal fabrications. In sheet metal forming the process is to gather the metal into defined areas. The pulley forming process is no exception and is achieved by superimposing axial loads on top of radial loads using a pressure-controlled tailstock. Whilst the headstock-mounted tooling is fixed, that part held on the tailstock can be powered axially under controlled pressure. This pressure is governed by the width of the workpiece which changes during the forming process. Experiments have been designed to provide an understanding of the pulley forming process and to verify numerical models. The latter has been taken the form of finite element simulations to enable prediction of metal flow, tool forces and potential sources of defects and failures. There are three objectives for conducting the experiments which have been investigated in this paper: 1. providing data to define the movements of the forming tools for the finite element model, including displacements and velocities, 2. understanding the effects of the pulley forming operation on the flow of material, and 3. validating the finite element model.

Abstract: This paper reports results from a stress, acoustics and vibration investigation of the ride and driveline components of a new 2-seater sports car. The work was aimed at giving design assurance information to designers and vehicle engineers working to compressed timescales. The paper focuses on two particular areas: design of the power train for NVH refinement, and design analysis of a suspension wishbone. In the first case, a dynamic model of drive shaft torsion effects was created to understand design relationships needed for high power, high torque performance car. In the second case, an investigation was made into the integrity of a suspension wishbone component when gauge thickness was reduced from 3 mm to 2 mm. The work described was carried out in a joint industry academic venture sponsored by Knowledge Transfer Partnership (KTP). It is from this background that the authors give some perspectives on vehicle development.