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The paper presents a new method, based on standard laboratory cup tests, for predicting the formability of materials; in the example provided, the forming potentials of four new materials are shown. The properties of stretchability and drawability, which are the principal factors defining a material's forming limits, may be assessed using the Olsen spherical cup test and the Swift flat-bottomed cup test. In the shape analysis procedure described, the minimum amount of deformation needed to fix a desired shape is determined. Then necessary adjustments to tooling for optimum sheet metal usage are made based on calculations from a new type of chart showing stretch forming ratio and draw forming ratio, providing a comparison of the formabilities of a number of materials.

Sheet metal forming difficulties often stem from splits in flanges. A technique to analyze strain at flange edges is described. The effects of stress concentrators, that is, tabs and cutouts, and burrs are shown. Some edge strain limits are also presented.

Successful automotive weight reduction with high strength-to-weight ratio steels has caused re-evaluation of the basic structural design parameters. This paper introduces the new concept of “Kinetic Modulus” which describes the nature of materials in motion. Kinetic modulus is influenced by stress and strain amplitude, yield strength and the number of loading cycles. The scope of kinetic modulus encompasses: elastic, secant, dynamic and tangent moduli; each of which is a specific case of kinetic modulus at a particular condition. Theoretical and experimental results are presented to support this concept. They show that high strength steel has higher dynamic stiffness and improved vibration response in structures as compared to that of lower strength steel. Thus, high strength steel (“Stiff Steel”) can be used advantageously in stiffness controlled automotive structures to achieve greater weight reductions.

Substitution of high-strength steels for low-carbon steels in automotive components to control spiraling weight increases in recent years is discussed. Material design interacting parameters are considered for efficient utilization of these materials. The economic justification for material substitution in terms of strength levels and grades are discussed in detail. Significant stamping experience in forming these materials for Lightweight Charger XL is presented in this paper. Examples of formed parts are shown and die modifications associated in forming some of the parts are also outlined.

The substantial development efforts made by the steel and aluminum industries have resulted in high strength-to-weight ratio materials that can be employed to achieve significant vehicle weight reduction. This total vehicle weight reduction is the sum of the initial weight savings attributable to lightweight material substitution and the iterative weight savings resulting from component weight interactions. The theoretical concept of vehicle interactive weight reduction was presented in a previous work. The present work reviews this theoretical concept and presents an experimental application: Charger XL, a lightweight materials development vehicle. Charger XL is 630 lb. (286 kg) lighter than its current, standard production counterpart. Lightweight materials substitution accounts for 375 lb (171 kg) while the interacting savings accounts for the remaining 255 lb (115 kg).

More than 77 kg (170 lbs.) of high strength steels (70 parts) are used in the new Chrysler Omni and Horizon models. Nearly 50 percent of these high strength metals is dent resistant steel. Why these high strength steels are used and what components are in production, are reported in this paper. The production experiences with these materials for major components are discussed. The development and application of dent resistant steel for hood outer panels are also reported. The advantages of using these high strength materials are also discussed in this report.

Automotive materials conversion to aluminum is increasing from 35 kgs in the 70's to more than 60 kgs average in the 1983 U.S. vehicles. To control mass, aluminum intensive vehicles with 180 kgs of aluminum are already in production for greater luxury, roominess, performance, and fuel efficiency. Optimization of aluminum designs and processing is achieved through the total design concept of “Putting It All Together”. A total of 225 kgs improves performance and maximizes the benefits for upsized vehicles by using current production components, drive trains, power plants, and press plant equipment.