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• A novel composite eco-structure made of plywood and flax/epoxy composite are studied. • A numerical model is used to predict the impact behaviour of the eco-structure. • The model improve the results of previous works to predict the plywood behaviour. An explicit numerical model is developed for the impact behaviour of a new composite eco-structure made of a plywood core and flax/epoxy composite skin. A constitutive orthotropic material behaviour is imposed to model the elastic response of plies of plywood core and flax skin. A stress-based modified Hashin-3D damage model with four independent failure criteria in tensile and compressive mode is incorporated for predicting the damage initiation. A strain threshold based exponential method is adopted to predict the damage scaling and its evolution. The above proposed model is implemented through user material subroutine (VUMAT) in ABAQUS Explicit. The developed model is validated with experimental low-velocity impact test results and can accurately predict the stiffness degradation, plateau, and post-peak softening of wooden plies. A good agreement with the better accuracy is achieved between the predictions and the test results. [ABSTRACT FROM AUTHOR]

The impact behavior of innovative wood based sandwich structures with plywood core and skins made either of aluminum or of fiber reinforced polymer (carbon, glass, or flax composite skins) was investigated numerically. The wood based sandwich structures were subjected to low-velocity/low-energy impacts. An explicit nonlinear numerical model based on volume elements with a cohesive layer was developed. A plastic wood law already implemented in LS-DYNA was used in association with composite type damage criteria. Comparisons with experiments in terms of layer deformations and overall contact laws during impact showed satisfactory results. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation of compression on pristine specimens and the compression after impact (CAI) response of wood-based sandwich structures. Nine different types of sandwiches, made with plywood core and different aluminum or composite (carbon or glass or flax fiber) skins, are studied. Impact energy levels were fixed at 5 J, 10 J and 15 J in order to create significant defects. Failure modes and damage scenarios are analyzed. The influence of different skins with plywood core is explained in terms of residual strength, residual stiffness, and specific properties. It is shown that this type of structure exhibits very interesting compression properties in terms of specific strength, which is superior to a reference sandwich used for aircraft flooring, and in terms of behavior, with large plateau areas that can be useful for crash issues. [ABSTRACT FROM AUTHOR]

The quasi-static behavior of innovative wood based sandwich structures with plywood core and skins made either of aluminum or of fiber reinforced polymer (carbon, glass or flax composite skins) was investigated. The wood based sandwich structures were subjected to three point static bending tests to determine their strength and failure mechanisms. Two different manufacturing processes, namely vacuum bag molding and thermo-compression, were used to manufacture the structures. The influence of some aspects of the different manufacturing processes on the flexural behavior of wood based sandwich structures are discussed. It is shown that manufacturing processes influence strongly the static responses. Failure modes and strengths are investigated during quasi-static bending tests. Bending tests showed that the mechanical characteristics were very high compared to those of a reference sandwich that is currently used for civil aircraft floors. This new kind of structure is environmentally friendly and very cheap, and seems promising for the transportation industry in general. [ABSTRACT FROM AUTHOR]