On a simultaneous use of fiber-Bragg-gratings and strain-gages to determine the stress-free temperature Tsf during GLARE manufacturing

The Impact of the Curing and Post-Stretching Process on the Stresses Distribution Around an Open Hole in Glare Laminate

“…The analysis made will also apply a final stretch to the specimen in order to evaluate the performance of the material once it is in service. Results obtained are compared with experimental data from [1], showing good agreement. This simulation capability will allow improving the whole manufacturing process, in order to minimize the residual stresses in the material and its final mechanical performance.…”

“…The high temperatures applied to the material during the resin curing process, required also to bond the composite and the metal, contract the layers within the laminate. The temperature at which this occurs is known as the stress-free temperature [1]. This bonding, together with the subsequent cooling of the laminate, results in residual stresses caused by the different thermal coefficient of each material.…”

The influence of the Curing Residual Thermal Stresses and Post-Stretching Process on Glare Laminate

“…During this process the mechanical bonding between the composite and the metal takes place. The temperature at which this occurs is known as the stress-free temperature [1]. Assuming that all layers deform equally during the cool-down process, due to the fact that the coefficients of thermal expansion are different for each material and directions this means that the plies develop thermally induced residual stresses.…”

“…Finally, taking into account the calculated residual stresses, which are also compared with experimental data [1], the effect of different post-stretching processes are analysed. The purpose of the post-stretching is to modify the stress balance within the GLARE material in order to improve the laminate mechanical properties.…”

Monitoring the Structural Health of Glass Fibre-Reinforced Hybrid Laminates Using Novel Piezoceramic Film

“…In order to meet these goals, several SHM systems already allow online measurements by structure-integrated or -applied sensors, which are divided into the following sensor types. Resistance strain gauges [ 7 , 8 ] Fibre optic sensors, e.g., fibre Bragg grating (FBG) strain sensors [ 9 , 10 , 11 ] Active or passive piezoelectric sensors [ 12 , 13 , 14 ] Sensors using the electrical properties: resistance, impedance, dielectric, etc. [ 15 , 16 ] …”