Failure Analysis of Composite Beams under Moving Loads

摘要

With the expanded use of composite materials in civil structures such as bridgedecks, a moving-load analysis would simulate a truck moving over a compositebridge. Almost all the available research concerning moving-load analysis concernswith results in the form of deflections and dynamic load factors; very little attentionhas been paid to the stress analysis and using the stress field to ascertain failure. Inthis research a finite element method employing h-p version finite elements is madeand analyzed to determine the failure of a composite beam under the action of amoving load. A computer code is written in MATLAB to accomplish this.Classical laminate plate theory (CLPT) and first order shear deformation theory(FSDT) are considered for the analysis of composite beams. A consistent formulationis used to reduce the composite plate theory to beams. The governing equations areobtained using Hamilton’s principle. Newmark’s time integration scheme is used todetermine the dynamic response in the form of the displacement field of the beam.The strain field is obtained using the kinematic relations and then the stress fieldusing the appropriate constitutive equations. Finally, the maximum stress failuretheory is applied to determine the factor of safety.Results are presented for a simply-supported beam subjected to a moving loadthat traverses the entire span of the composite beam. The stress field and factors ofsafety based on the CLPT is compared with that of FSDT. A parametric study isconducted by considering different laminates and different fiber volume fractions.