Alternative Title

Civil Engineering Study 83-4


I. INTRODUCTION In February 1981, the "Guide for Preliminary Design of Sheet Steel Automotive Structural Components" was issued by American Iron and Steel Institute (AISI) for assisting automotive structural designers to achieve weight reduction through the efficient utilization of carbon and high strength steels. 1 These design recommendations were based primarily on the 1968 Edition of the AISI "Specification for the Design of Cold-Formed Steel Structural Hembers,,2 but contained the following major differences with regard to the AISI Specification, which was written 'for the design of buildings: 1,4 a. The design expressions presented in the Guide are based on an ultimate strength basis. b. The range of applicability is restricted in some instances because of some simplified expressions in the Guide. c. The design expressions are extended to materials with yield strengths ranging up to 80 ksi. The AISI Specification was revised in 1980. 3 Some of the design criteria were revised and others were added in keeping with technical developments and the results of continued research programs sponsored by the American Iron and Steel Institute. The significant changes made in the 1980 Edition of the AISI Specification for building design are related to the following subjects: materials, webs of flexural members, inelastic reserve capacity of flexural members, arc welds, bolted connections, wall studs, channels and Z-sections used as beams, and tests for special cases. 3 The design of automotive components may be affected by the revisions cop.cerning webs of flexural members and inelastic reserve capacity of flexural members. Since early 1982, a research project entitled "Structural Design of Automotive Structural Components Using High Strength Sheet Steels" has been conducted at the University of Missouri-Rolla under the sponsorship of American Iron and Steel Institute. objectives of the project are: The primary a. to determine the characteristics of high strength automotive sheet steels that may influence the performance of the steels in structural application, b. to determine if the existing design procedures are appropriate, and c. to develop new design procedures if necessary. In order to achieve the above objectives, the following three phases of research work were planned for the project: I. Preliminary Study II. Structural Research III. Development of Design Criteria The preliminary study (Phase I) included a review of the literature dealing with automotive structures, a study of typical mechanical properties and stress -strain curves for a selected group of high strength sheet steels, and a critical review of various AISI specifications for the design of cold-formed steel members. Phase I was completed in January 1983. 5 The present report deals with a part of Phase II. It contains the results of a brief study of the load-carrying capacities of hat sections used as flexural members in automotive structures. This study was based on the tests conducted by Levy6 and Vecchio 7 for the following design considerations: 1. Moment resisting capacity 2. Bending capacity of webs 3. Shear capacity of webs 4. Combined bending and shear in webs 5. Web crippling 6. Combined bending and web crippling In Section II, the provisions of the 1981 Guide and the 1980 Specification are reviewed for each of the design considerations mentioned above. Section III contains an evaluation of the available experimental results and a discussion of the validity of current AISI design procedures. A modification of the design expressions for web crippling of beams cold-formed from high strength steels is given in Section IV, and topics for future study are proposed in Section V.


Civil, Architectural and Environmental Engineering

Research Center/Laboratory(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures


American Iron and Steel Institute

Appears In

Structural Series


Missouri University of Science and Technology

Publication Date


Document Version

Final Version


© 1983 Missouri University of Science and Technology, All rights reserved.


Third Progress Report

Document Type

Report - Technical

File Type