Civil Engineering Study 93-1
INTRODUCTION In the past, a considerable amount of theoretical and experimental research has been undertaken to study material properties and the behavior of structures under dynamic loads and impact loads. For the purpose of investigating the structural behavior and strength of cold-formed steel members under dynamic loads, a research project was conducted at the University of Missouri-Rolla from January 1988 through December 1991 to study the effect of strain rate on mechanical properties of sheet steels and the structural behavior and strength of cold-formed steel members. The test results of material properties, stub columns, and beams with evaluations were summarized in the Eighteenth Progress Report 1. Because the previous studies were limited only to the structural members which were assembled with the same material in a given section, the research work reported herein under the sponsorship of the American Iron and Steel Institute (AISI) was concentrated on a study of the structural strength of hybrid automotive structural components using different sheet steels. In the first phase of the project, two selected sheet steels (25AK and 50SK) have been tested for establishing the mechanical properties in tension and compression under different strain rates. The nominal yield strengths of these two sheet steels are equal to approximately 25 and 50 ksi and the range of strain rates used in the test varied from 10- 4 to 1.0 in./in./sec. Details of the tension and compression coupon tests were presented in the Seventeenth Progress Report 2. Due to the lack of drop tower test equipment at the University of Missouri-Rolla, a total of fifty-two (52) drop tower tests of stub columns were conducted at General Motors Corporation during the Summer of 1992. The impact velocities used in the drop tower tests were 28.5 and 43.2 km/hr. The research findings are presented in Reference 3. At the University of Missouri-Rolla, the study of stub columns including hybrid sections fabricated from 25AK and 50SK sheet steels subjected to dynamic loads was initiated in January 1993. Ninty-six (96) box-shaped stub columns and forty-eight (48) hat-shaped stub columns were tested under the strain rates varied from 10-4 to 10- 1 in./in./sec. The test results of a total of 144 test specimens were reported herein. Among these specimens, 80 specimens were hybrid sections. In Chapter II of this report, the literature review is related to the structural strength of steel members under dynamic loading conditions. The experimental investigation of the structural behavior of stub columns subjected to static and dynamic loads are discussed in Chapter III. The test data of specimens fabricated from two types of sheet steels are evaluated in Chapter IV. summarized in Chapter V. Finally, the results of stub column tests are summarized in Chapter V.
Civil, Architectural and Environmental Engineering
American Iron and Steel Institute
Wei-Wen Yu Center for Cold-Formed Steel Structures
Cold-Formed Steel Series
Missouri University of Science and Technology
© 1993 Missouri University of Science and Technology, All rights reserved.
Report - Technical
Pan, Chi-Ling and Yu, Wei-wen, "Design of automotive structural components using high strength sheet steels effect of strain rate on the structural strength and crushing behavior of cold-formed steel stub columns" (1993). Center for Cold-Formed Steel Structures Library. 45.