Investigation of Skin-Core Debonding in Sandwich Panel Structures with PMI Foam Cores

The choice of the materials used for the core and skin of a sandwich structure plays an extremely important role in the skin-core interfacial behaviour. In this paper, three PMI foams are used as core material and the effect of foam type in the skin-core interfacial response is examined

Characterisation and Modelling of Polymeric Foams for Applications in Energy Absorbing Structures

Two polymeric foams have been characterised to develop a simple calibration process for extracting the parameters which are required by the material model available in the commercial FE package Abaqus. Indentation tests with DIC were conducted to study the validity of the proposed method

Investigation of skin-core debonding in sandwich structures with foam cores

Debonding between the skins and the core in a sandwich structure is a critical failure mode in automotive applications; once debonding occurs, the load carrying capacity of a sandwich structure drastically decreases. In the present paper, the effect of using three core materials, with different cell characteristics, on the interfacial strength between the foam cores and a CFRP skin is investigated through mechanical testing and numerical modelling. A key finding is that foams with a coarse cellular structure favour a high resin uptake at the interface during the manufacturing process, which results in a stronger interfacial bonding between the foam and the CFRP. During Mode I loading, the thick resin layer at the interface postpones crack initiation and kinking in the core, whilst under Mode II, this resin layer delays the collapse in compression of foam cells under the crack tip. Thus, the importance of including this thick resin layer in the FE modelling was demonstrated. Finally, as the CZM was shown to be unable to predict the unstable crack propagation within the core, an alternative approach was suggested which has the significant benefit of not requiring experimental testing of the interface between the skin and the core

Investigation of skin-core debonding in sandwich structures with foam cores

Debonding between the skins and the core in a sandwich structure is a critical failure mode in automotive applications; once debonding occurs, the load carrying capacity of a sandwich structure drastically decreases. In the present paper, the effect of using three core materials, with different cell characteristics, on the interfacial strength between the foam cores and a CFRP skin is investigated through mechanical testing and numerical modelling. A key finding is that foams with a coarse cellular structure favour a high resin uptake at the interface during the manufacturing process, which results in a stronger interfacial bonding between the foam and the CFRP. During Mode I loading, the thick resin layer at the interface postpones crack initiation and kinking in the core, whilst under Mode II, this resin layer delays the collapse in compression of foam cells under the crack tip. Thus, the importance of including this thick resin layer in the FE modelling was demonstrated. Finally, as the CZM was shown to be unable to predict the unstable crack propagation within the core, an alternative approach was suggested which has the significant benefit of not requiring experimental testing of the interface between the skin and the core