A Theoretical Study on the Onset of Interlayer Shear Damage in Layered Composite Beams Subjected to Thermal Patch Loading

This study presents an analytical investigation on the initiation of interlaminar failure in laminated composite beams subjected to localized thermal patch loading. The necessity of this study is to understand the structural integrity and inter-laminar stresses of the beam structures subjected to localized loads. Two beam configurations, {0/90} and {0/90/0} are analyzed under different aspect ratios using higher order refined trigonometric, parabolic, first order shear deformation theories (TSDT, PSDT, FSDT) and classical beam theory (CBT). Non-dimensional displacements and stresses were extracted to assess interlaminar stress behaviour and corresponding shear failure initiation. Results demonstrate that localized temperature gradients significantly influence the transverse shear stresses, which serve as indicator of possible delamination onset. The analysis highlights the suitability of shear failure index-based evaluation for predicting early delamination in thermally loaded composite beams.