Stress concentrations play an important role in determining how much weight is saved by substituting aluminum for steel while maintaining equal stiffness. In general, lower stress concentrations are associated with lower weight savings. This is true because an aluminum part is made of thicker material than a steel part; it is this extra thickness, which redistributes the stresses, which reduces the stress concentration and makes the part more efficient. It is this greater efficiency, rather than the specific modulus of aluminum, which allows an aluminum part to be lighter but just as stiff as a steel part. Two mechanisms have been identified as causing stress concentrations in parts with complex geometry: curved beams in flexure and localized flat plate bending. A study was made on the reinforcement of a T-joint. It was shown that reducing stress concentrations with proper reinforcement greatly increased the stiffness and lowered the maximum stress in the joint. Stress concentrations were due to curved beams in flexure and localized flat plate bending were identified. Best results were achieved by bulkheading the joint and adding a center layer. These reinforcements reduced the weight saving gained by substituting aluminum for steel, reduced stress concentrations, and increased the stiffness compared to the baseline joint. Previous studies have concentrated on building lightweight steel bodies largely by substituting highstrength steel alloys and downgaging. The strategy has achieved weight saving of about 25 %. Further weight reductions may be possible by properly reinforcing joints and other complex parts to reduce stress concentrations. This increases the stiffness of the part without adding much weight, as well as reducing stresses. This greatly reduces the weight advantage that aluminum has over steel, while reducing weight and improving quality in a cost-effective way.
Causes of weight reduction effects of material substitution on constant stiffness components
Ursachen der Gewichtsreduzierungswirkungen in der Werkstoffsubstitution bei Bauteilen konstanter Steifigkeit
2002
10 Seiten, 18 Bilder, 5 Tabellen, 9 Quellen
Aufsatz (Konferenz)
Englisch
Causes of Weight Reduction Effects of Material Substitution on Constant Stiffness Components
SAE Technical Papers | 2002
|Causes of weight reduction effects of material substitution on constant stiffness components
Kraftfahrwesen | 2002
|British Library Conference Proceedings | 2002
|Estimating Weight Reduction Effects of Material Substitution on Joints with Constant Stiffness
SAE Technical Papers | 2002
|Estimating weight reduction effects of material substitution on joints with constant stiffness
Kraftfahrwesen | 2002
|