STEEL AND GFRP BEAMS/HEAVY-DUTY VEHICLE LEAF SPRINGS UNDER CYCLIC LOADING.
Technological advances in many areas of the industry require of lighter and stronger
materials. Especially in the automotive industry, composites have replaced many metallic
components. The scope of this analysis is to determine how appropriate composite
materials are for cyclic loading applications such as in the case of leaf springs. AISI
4130, AISI 6150, E glass fiber/epoxy and S... read more2 glass fiber/epoxy were examined to determine
their fatigue life and failure behavior. Experimental results, theoretical calculations
and finite element analysis were performed in order to examine the important parameters
that affect the fatigue life of these materials, and determine the material that will
have longer life. Induction of a compressive residual stress field in a steel component,
as a result of surface and heat treatment of the material, enhances the fatigue life of
the material and its performance. Different ply stacking sequences of a laminate result
in structures of different strength and fatigue life. Among the materials examined AISI
6150 and S2 glass fiber/epoxy have longer lives, and the steel showed longer lives than
the composite at higher applied stresses. Hybrid structures were constructed from AISI
6150 and S2 glass fiber/epoxy, and examined through experimental testing and theoretical
calculations, in order to determine their applicability as leaf spring structures.
Comparison of the steel, composite and hybrid structures, together with an economic
analysis of the manufacturing process for steel and composite leaf springs, showed that
composites provide the lightest, stronger and more economical option for leaf spring
Thesis (Ph.D.)--Tufts University, 2012.
Submitted to the Dept. of Mechanical Engineering.
Advisors: Anil Saigal, and Douglas Matson.
Committee: Anil Saigal, Douglas Matson, Michael Zimmerman, Georgios Savaidis, and Gary Leisk.
Keyword: Mechanical engineering.read less