Evaluation of the influence of cooling rate on residual strain development in unidirectional carbon fibre/polyphenylenesulfide laminates using embedded fibre Bragg grating sensors

Abstract

This study investigates the influence of cooling rate on the residual strain of the carbon fibre/polyphenylenesulfide unidirectional laminates. Three different cooling rates (−300℃/min, −100℃/min and −10℃/min) were applied to simulate a wide range of cooling conditions. The crystallisation behaviour which depends on the cooling rate was evaluated using differential scanning calorimetry. A process monitoring test was then conducted using embedded fibre Bragg grating sensors. In-plane transverse strain of carbon fibre/polyphenylenesulfide unidirectional laminates was measured and the results were presented based on the crystallisation behaviour determined by differential scanning calorimetry. Furthermore, residual strain change after subsequent annealing was examined. This study successfully demonstrates the effectiveness of in situ process monitoring using fibre Bragg grating sensors for evaluating material behaviour of thermoplastic composites during rapid heating and cooling under realistic processing conditions.

Assessing residual stress redistribution during annealing in thick thermoplastic composites using optical fiber sensors

“…tool–part interaction). 14 Three kinds of molding conditions were set. Because the main difference in the three conditions was the cooling rate, they were defined as slow cooling (SC), medium-speed cooling (MC), and fast cooling (FC).…”

“…Fiber Bragg grating (FBG) is a type of optical fiber sensors widely applied to in situ process monitoring. [11][12][13][14][15] They are highly sensitive to changes in strain and temperature. The optical fiber used in this current study is made of silica glass coated by polyimide.…”

The influence of skin-core residual stress and cooling rate on the impact response of carbon fibre/polyphenylenesulphide

“… Q E N ' is the endothermic heat per unit mass determined by melting fully crystallized neat PPS resin (150.4 J g −1 ). 13 The mass fraction W f of the fibres was measured as 0.66. During the preheat process, Q EN and Q EX were measured to be 13.8 J g −1 and 16.7 J g −1 , respectively.…”

Investigation of residual stresses induced by composite forming using macro-micro simulation

“…9 However, it is quite difficult to measure residual stresses in a composite using nondestructive testing directly. 10 Although the residual strain during composite forming can be measured by an in-situ method like that using an optical fiber strain sensor, 11 the residual stresses in an RVE have not been measured to date. Micro FE simulation provides a feasible approach to study micro-residual stresses as long as the methodology and material data are reliable.…”