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Accurate finite element crash simulations of side impact depend upon a thorough understanding of dynamic tube bending. There is a need to understand the dynamic bending mode of square sections (equivalent of automotive structural parts) to obtain a greater confidence in CAE. This work varied strain rate and material definitions, such as Cowper-Symonds vs Zerilli-Armstrong, as well as initial velocity and yield strength. The results show that most of the plastic work is done between strains rates of 30 - 300/s and strains up to 0.3. Peak strain rates were marginally above 1000/s with maximum strain greater than 1. When the strain rate definition and material model were modified, it was shown that a higher yield stress produced a higher reaction force. These results would suggest that the strain rate sensitivity needs to be carefully identified for accurate crash simulations.

A Split Hopkinson Pressure Bar (SHPB) was used to obtain dynamic behaviour of various steels at large strains and high strain rate. The dynamic loading response was compared between mild steels and cold rolled high strength steels, Dual Phase 590 and TRIP 780. Only sheet samples were available for the high strength steels, and thus confirmation tests were carried out on mild steel to determine whether behaviour of sandwiched samples were equivalent to normal bulk samples. The effect of pre-straining and bake hardening on dynamic behaviour of sheet metals was then investigated. Preliminary results show a difference between the bake hardening effect on pre-strained Dual Phase and TRIP steels. Bake hardening increased the mass specific energy absorption for the pre-strained Dual phase sample, whereas the pre-strained TRIP sample mass energy absorption decreased. Further work is necessary to verify this difference and understand the material behaviours.

This paper identifies the need for AI based tools to supplement CAD/FEA methods. The approach discussed focuses on the capture and feedback of part based case lessons or issues that form a knowledge base for future use. Key aspects of a system to achieve this are presented. These include: Issue or problem data to be collected at source, the system to be visually based, enhance current job function, integrated with existing IT systems and work procedures, data to be readily accessible and consistent, modular approach functional access to data. The elements of a knowledge capture system for the stamping industry based on the above is discussed.

The springback of simple geometries can be predicted through theoretical analysis, however problems arise when transferring this analysis to the manufacturing environment. To determine why this is the case, a study of small curvature free bending through theoretical analysis, manufacturing data and Finite Element (FE) simulation was completed. The theoretical analysis provided an understanding of the behavior of springback and gave accurate predictions in a controlled environment. The manufacturing and Finite Element data verified the trends predicted by theory, but lacked in accuracy. The paper concludes by proposing a prediction method based solely on the geometry that is well defined in both environments.

A discrete event model was used to examine the effect of machine downtime and operating policy on the long-run average cost of an automotive stamping line. Operating policy refers to the selection of a target batch size and the circumstances under which a line stoppage will lead to the current batch being abandoned. It is assumed that the abandon/resume decision is based solely on the severity of the problem (ie repair cost) and the fraction of the batch completed. A method of identifying low cost operating policies is presented using data obtained from a real stamping plant. It is found that, within a single part framework, this approach results in significantly lower average costs than are currently achieved. It is also demonstrated that by varying the model parameters it is possible to measure the potential benefits arising from process modifications (eg decreased die-set times).

This work examines the design and implementation of a new runner and gating system for an existing cast iron exhaust manifold. Three designs were tested. Pressurized and unpressurized systems were trialed to determine which system produces better results in gravity casting. Runner, gate and sprue areas were varied to control the peak linear velocity during filling. These trials gave high defect levels for peak velocities over 2.0 m/s in pressurized and unpressurized systems, and the pressurized systems significantly reduced slag inclusions. A pressurized system with larger runner sections reduced the casting defect rate tenfold when peak gate velocity was limited to 1.0 m/s.

This work investigates the effect of elastic deformation of the press and die in a double action press on system performance during draw die forming. A simple linear elastic model of the complete press system was developed to show that the relative stiffness of system components controls blankholder force variation during the stroke. Calibration of the analytical model with data taken from a production press shows that the simple model explains real global system behaviour very well; and that varying system compliances can desensitise the press system to changes affecting the binder gap during the stroke. The experimental data suggests that real press and tool systems do not have an appropriate combination of system compliance, which causes large variations in blankholder force during the stroke. This model will be a useful tool for die designers and process engineers for assessing the potential impact of blankholder force variation during die design.