The Application of Thermoelastic Stress Analysis to Evaluate Debond Damage in Composite Sandwich Structures

Abstract

The work described in the paper investigates the stresses in the vicinity of a debond between the face sheet and core in a foam core / composite sandwich beam. Experiments were conducted in which the damaged side of the beam was loaded in compression in a four point bend test. Thermoelastic stress analysis (TSA) was used to obtain a measure of the stress field in the central part of the beam to evaluate its potential for damage detection and assessment. It is shown that TSA is capable of both identifying the damage and assessing its severity in terms of the remnant load carrying capacity of the beam. Fatigue tests were also performed, which showed that the cyclic load applied as a necessity for TSA did not cause the damage to grow, thereby demonstrating the potential of TSA as a non-destructive method for inspecting sandwich structures.

Quantitative Calorimetry and TSA in Case of Low Thermal Signal and Strong Spatial Gradients: Application to Glass Materials

“…They are used to access to the thermoelastic and the calorimetric effects accompanying the deformation of materials in order to better understand and model their mechanical behavior. Most materials have already benefited from these techniques including smart memory alloys [3], aluminum alloys [4], polymers [5], composites [6][7][8][9][10] and elastomers [11,12]. These materials exhibit temperature variations in the range of one degree or more.…”

Thermomechanical characterization of stress localization in glass: An experimental and numerical study

“…() Quantitative calorimetry allows the study of several phenomena such as Lüders or Portevin‐Le Chatelier plastic instabilities,() rubber elasticity,() or mechanical fatigue. () Most materials have already benefited from these techniques including smart memory alloys,() aluminum alloys,() polymers,() composites,() and elastomers. () These materials exhibit temperature variations in the range of one degree or more.…”