Inverse identification of process-induced shrinkage strain for a B-stage thermoset resin in woven pre-impregnated lamina via warpage analysis
Abstract
Multilayer composites are often found in industrial applications where pre-impregnated (pre-preg) and laminated plies are stacked and hot pressed. Along this process, the B-stage resin within pre-pregs cures and shrinks, generating residual stresses in the assembly which need to be quantified. The B-stage resin in pre-preg is seldom available, preventing the characterization of its shrinkage strain. Existing methods enable to identify the in-plane effective shrinkage of pre-impregnated lamina, based on the warpage measurements of a bilayer assembly assuming homogeneous thickness of layers. An extension is proposed to estimate the apparent shrinkage strain of the B-stage resin. A difficulty originates from heterogeneous properties across the bilayer. Indeed, the hot pressing induces a local variation in the resin volume fraction due to the resin flow. These fluctuations in thermomechanical behavior and effective shrinkage strain of the lamina are quantified, as a function of the ply thickness, by a two-scale homogenization method. By considering the thickness-dependent behavior of the pre-preg, the experimental warpage of the bilayer is modeled and recovered accurately through the estimation of the apparent shrinkage strain of the resin. As a direct outcome, the effective process-induced shrinkage components are determined even in the out-of-plane direction through numerical homogenization.
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BibTeX
@article{leicht2026inverse,
title = {{Inverse identification of process-induced shrinkage strain for a B-stage thermoset resin in woven pre-impregnated lamina via warpage analysis}},
author = {Mickaël Leicht and Gautier Girard and Norman Mathieu and Baptiste Arati and Aymeric Lagadec and Fabio Coccetti and Sébastien Mercier},
journal = {Composites Part A: Applied Science and Manufacturing},
year = {2026},
month = sep,
doi = {10.1016/j.compositesa.2026.110304},
url = {https://hal.science/hal-05776659v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Inverse identification of process-induced shrinkage strain for a B-stage thermoset resin in woven pre-impregnated lamina via warpage analysis
AU - Mickaël Leicht
AU - Gautier Girard
AU - Norman Mathieu
AU - Baptiste Arati
AU - Aymeric Lagadec
AU - Fabio Coccetti
AU - Sébastien Mercier
PY - 2026
DA - 2026/09/22
JO - Composites Part A: Applied Science and Manufacturing
DO - 10.1016/j.compositesa.2026.110304
UR - https://hal.science/hal-05776659v1
AB - Multilayer composites are often found in industrial applications where pre-impregnated (pre-preg) and laminated plies are stacked and hot pressed. Along this process, the B-stage resin within pre-pregs cures and shrinks, generating residual stresses in the assembly which need to be quantified. The B-stage resin in pre-preg is seldom available, preventing the characterization of its shrinkage strain. Existing methods enable to identify the in-plane effective shrinkage of pre-impregnated lamina, based on the warpage measurements of a bilayer assembly assuming homogeneous thickness of layers. An extension is proposed to estimate the apparent shrinkage strain of the B-stage resin. A difficulty originates from heterogeneous properties across the bilayer. Indeed, the hot pressing induces a local variation in the resin volume fraction due to the resin flow. These fluctuations in thermomechanical behavior and effective shrinkage strain of the lamina are quantified, as a function of the ply thickness, by a two-scale homogenization method. By considering the thickness-dependent behavior of the pre-preg, the experimental warpage of the bilayer is modeled and recovered accurately through the estimation of the apparent shrinkage strain of the resin. As a direct outcome, the effective process-induced shrinkage components are determined even in the out-of-plane direction through numerical homogenization.
SN - 1359-835X
ER -