Abstract
Sandwich structures are nowadays widely used due its excellent characteristics of matching light weight with high bend stiffness. However the complex nature of its composition turns the estimation of its mechanical elastic properties challenging. The objective of the present article is to propose an analytical/experimental model to estimate the orthotropic elastic properties of this composite material. To accomplish this objective a theory of anisotropic plates is used together to an extensometric experimental approach. A sandwich laminate specimen, instrumented with strain gages, was submitted through pure bending loading by a mechanical testing machine on a 4-point bending apparatus. The result of this research was the determination of 4 orthotropic elastic properties of the sandwich laminate specimen, namely: the longitudinal and transversal Young moduli, the shear modulus, and the Poisson’s ratio.
Highlights
Composites materials, as sandwich laminates, have been widely used for structural purposes
A heterogeneous displacement field was observed by a CCD camera and measured by a digital image correlation (DIC) technique
The measured displacement field and the subsequently computed strain field were compared with a finite element simulation of the same experiment
Summary
Composites materials, as sandwich laminates, have been widely used for structural purposes. Where: F is the applied load; l is the distance between the upper roller anvil and the immediate adjacent lower roller anvil (see Fig. 1a); t1 is the woven lamina thickness; tc is the core thickness; b is the specimen width Note that for this simplified analytical model it is supposed that all loads are only resisted by the woven laminas, since the core material has a much lower stiffness (Kassapoglou 2010). The normal local strains, at a general given angle θ, in relation to the global axes, shown, can be estimated as in Lekhnitskii (1981): where: E1 and E2 are the lamina elastic moduli for, respectively, 11 and 22 axis global directions; G12 is the lamina shear modulus; ν12 is the lamina Poisson’s ratio. Notice that Eq 3 can be rewritten in a matricial form, with 4 lines, one per strain gage of angle θn
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call