A microstructural approach for modelling flexural properties of long glass fibre reinforced polyamide6.6

Abstract

This paper focuses on the development and the validation of flexural modulus and flexural strength predictive models of long glass fibre reinforced polyamide 6.6 (PA66). Based on previous injection moulding optimization of 40 wt% long glass fibre PA66, a microstructure analysis was investigated on glass fibre reinforced PA66 by varying the parameters of the material (fibre length, fibre content, fibre diameter). In a first phase, analytical models established within the framework of the processing condition limits previously determined have been elaborated. These models lead to a good experimental/calculation correlation but remain limited to a mould and part design. In a second phase the flexural modulus and maximal flexural stress have been then estimated from structural models based on a five layer morphological description of the composites (local residual fibre length, local fibre content and fibre orientations). The long glass fibre PA66 composites were characterized in terms of fibre content distribution model and fibre orientation model through the part thickness. The experimental/model correlation was achieved whatever the process variability is (mould, material and processing conditions) both for the flexural modulus or flexural strength. The models have been then validated with an industrial part. Finally, a correlation between the two studied properties has been revealed depending on the nature of the composite matrix (PA66, PA6 or PP).

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“…The smallest value is around 0.3 mm when a maximum of 11 mm is sometimes reached, and therefore the composite should be qualified as semi-long fiber material. 26,28…”

“…The smallest value is around 0.3 mm when a maximum of 11 mm is sometimes reached, and therefore the composite should be qualified as semi-long fiber material. 26,28 Three temperatures representative of common industrial specifications are considered in this study: 23 C, 60 C, and 85 C. Only positive temperatures are chosen, to represent desert-like conditions responsible for creep. Main properties of each constituent of PPGFL40 are specified in Table 1.…”

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