Experimental Verification of Numerical Calculations with the Use of Digital Image Correlation

Abstract

The article presents the results of research work performed under the TEBUK project, aiming primarily to develop a reference methodology for assessing the impact of damage on the strength of structures made of carbon epoxy prepregs. The tests described in the paper were concerned with a fragment of the structure (FS) of the TEBUK project demonstrator, made of carbon epoxy composite, with an artificial circular delamination measuring 40 mm in diameter. Numerical and experimental test of FS have been performed under quasi-static compression load. The buckling of the skin observed in the delamination area, as well as the propagation of the latter were investigated. The numerical calculations have been performed with the use of the commercially available MSC Marc/Mentat calculation suite based on the Finite Elements Methods. Results of the numerical calculations have been compared with experimental measurements made with the use of the Digital Image Correlation (DIC) method. The tests performed aimed to provide a preliminary verification of the numerical model. The results obtained have shown a very good correlation between the numerical and experimental results concerned with critical load levels at which stability of the layers separated by delamination is lost (buckling). The lack of convergence of the numerical model’s results after exceeding the critical load values has rendered it impossible to unequivocally compare the results concerned with propagation of the delamination area.

Determination of In-Plane Shear Properties of Laminate with V-Notch Rail Shear Test and Digital Image Correlation

“…Modern aircraft design, as well as the production process, rely heavily on numeric simulations, for instance, with the use of finite element analysis (FEA). Nonetheless, these simulations have to be verified and validated for being deemed as reliable [1,2]. The obvious method of validation is performing mechanical tests of modelled components.…”

“…DIC has been successfully used in many applications, e.g. validating FEA models of wing parts [2], assessing material performance under biaxial loading [8] or measuring composite material properties (Young modulus, Poisson ratio, shear properties), among others [3,5,6,9,10]. Among these, shear measurements seem to be of high value -shearing of material is complex process with multi-axial, often nonuniform state of strain.…”