The materials can vary in type and mechanical properties in addition to property specific orientation particularly pertaining to wood and composites. There are an infinite number of laminate types that can be developed. These materials can be categorized into three basic areas, core materials, high strength and stiffness skins and outer protective layers. Core materials typically serve the function of connecting and spacing of the skins to develop stiffness and strength in a sandwich arrangement. The key property of core materials is shear strength to insure shear conductivity between the skins, thus the ability to sustain loads and bending.
Core materials are normally wood, honeycomb and structural foams.
The outer structural layer or skins traditionally are either metal or composite, either in combination with a core material or a multitude of high strength and stiffness layers. Composites are well suited for large deflection applications where high strain capability and fatigue is required. Typically they are more corrosion and environmentally resistant than metals. Composite materials in a lamina form are applied in the form of precured, prepreg or B stage and wet layup configurations. The final group of laminae is made up of thermoplastic and thermoset materials, which act as a covering to the laminate structure.