Experimental investigations on flexural behaviour of delaminated carbon/epoxy composite using three dimensional digital image correlation

Abstract

In semi automated manufacturing processes of multilayered carbon fiber reinforced composites, defects are induced. These defects cause reduction in service life of the products and lead to decrease in structural performance. In the present work, carbon fiber reinforced epoxy composite laminate with a stacking sequence of [0/0//45/−45/90/45/−45/90/90/−45/45/90/−45/45/0/0] was fabricated by hand lay-up method using vacuum bagging technique. An artificial defect to create pre-delamination was located in this composite between 0° and 45° plies at the centre of laminate. Experiments were conducted in four-point bending to determine the stiffness behavior of composite laminate and study other damage patterns occurred due to the existence of pre-delamination. The probable reasons for occurrence of other damage forms are explained in detail. Three-dimensional digital image correlation (DIC) technique was employed to determine displacements and strains of the specimen. The out of plane displacement due to local buckling against the bending load was also quantified.

The optimization of bellows convolutions in bellows pump for better stress distribution

“…Thus, DIC, a method for obtaining deformation information of specimen through the correlation calculations of the digital images before and after deformation, was selected to measure the strain on convolutions. 29 There are also some limitations for DIC: for example, it can only collect outer surface images of the bellows, and applying pressure during the measurement becomes impractical for the shooting of CCD cameras that would be affected by the pressure device. Therefore, we can only measure the strain on the outer surface of outer convolutions to indirectly prove the validity of the optimization.…”

Analysis of 3D composite preform contour locking parameters based on vibration characteristics

“…Here, F d ( X , T d )= ρ d A d ( L ( T d )- X ) v d , T , which is the inner tension. I d is the side rod section moment of inertia, where I d = πD r 4 /64, and D r is the side rod section diameter.…”

“…As science and technology continue to develop while the demand for high-performance composites continues to increase, higher requirements are being placed on the Threedimensional(3D) reinforced composite [1][2][3][4] preform process. Therefore, how to optimize the process parameters [5][6][7] in the weaving process 8,9 to improve composite preform quality and precision has now become a current focus of research.…”

Hybridization effect of Kevlar and glass fibers on CFRP composite under low velocity impact: Numerical simulations

“…Investigating the stacking sequence of fiber layers in hybrid composites plays a vital role in improving impact resistance. Recent studies [31][32][33][34] indicated that hybridization unites the ductile fiber having good impact resistance with high stiffness fibers to characterize the mechanical properties.…”