This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Causes of Weight Reduction Effects of Material Substitution on Constant Stiffness Components
ISSN: 0148-7191, e-ISSN: 2688-3627
Published March 04, 2002 by SAE International in United States
Annotation ability available
The substitution of lightweight materials, such as aluminum or magnesium alloys, to produce lightweight car bodies, has been the subject of intensive research in resent years. It has been established that an aluminum body is lighter than a steel body for constant stiffness. The causes of this weight reduction have not been established. In particular, since the specific modulus (modulus of elasticity/density) of steel, aluminum and magnesium are nearly identical, there is no easy answer for their ability to reduce weight.
In this paper, it is shown that there are stress concentrations in thin walled structures, which are dependent on the thickness of the material. These stress concentrations appear in joints and other parts with complex geometry and loading conditions. For example, the flanges on a curved beam in flexure have an effective (load bearing) width, which increases as the material is thickened. A part made of thicker material uses its material more efficiently (has a higher percentage of load-bear material) than a thinner part. This thickness dependence is important because thin-walled parts made from lightweight materials, such as aluminum, are thicker than their steel counterparts; hence the parts made from lightweight materials use their material more efficiently. It is further shown that reducing the stress concentrations through better reinforcements produces significant weight reduction effects and also reduces the weight reduction effects of substituting aluminum for steel. Thus a strong, lightweight body can be achieved using steel and proper design of joints and other complex geometry parts. This is a more cost-effective way of achieving a lightweight body.
CitationPatton, R. and Li, F., "Causes of Weight Reduction Effects of Material Substitution on Constant Stiffness Components," SAE Technical Paper 2002-01-1291, 2002, https://doi.org/10.4271/2002-01-1291.
- Skalny, Paul “Government-Industry Partnership for Improving the Military's and Nation's Trucks: The 21st Century Truck Initiative” (SAE Paper No. 2000-01-3420 ) Warrendale, PA Society of Automotive Engineers
- Das, Sujit Curlee, Randall Schexnayder, Susan “Materials used in New Generation Vehicles: Supplies, Shifts and Supporting Infrastructure,” Oak Ridge National Laboratory August 1997 1 10
- Nardini, D. Seeds, A. “Structural Design Considerations for Bonded Aluminum Structured Vehicles” (SAE paper number 890716 ) Warrendale, PA Society of Automotive Engineers
- Ashby, M. F. Materials Selection in Mechanical Design Pergamon Press Oxford, UK 1993 56 69 132 151
- Von Karman, T Zeitshrift des Vereines deutscher Ingenieure 55 1911 1889
- Timoshenko, S. “Bending Stresses in Curved Tubes of Rectangular Cross-Section,” Trans. ASME 45 1923 135 140
- Anderson, C. G. “Flexural Stresses in Curved Beams of I- and Box Sections,” Proc. I.Mech.E. November 3 1950 162 295 305
- Bleich, H. “Die Spannungsverteilung in den Gurtungen gekruemmter stabe mit T- und I-formigem Querschnitt,” Der Stahlbau, Beilage zur Zeitschrift, Die Bautechnik 6 1 Jan. 6 1933 3 6 Navy Dept. The David W. Taylor Model Basin Translation 228 January 1950
- “Ultralight Steel Auto Body Final Report,” American Iron & Steel Institute Washington D. C. May 1998