Bridging the Effect of the Impactor Head Shape to the Induced Damage during Impact at Low Velocity for Composite Laminates

Abstract

The present paper presents an investigation and analysis study of the effect of the head shapes of the impactor on the damages observed during low-velocity impact on T700/Epoxy composite laminate. Two types of impactors were investigated: hemispherical and flat-face. A new criterion based on the LARC05 damage model was linked as a LARC_VUMAT subroutine to simulate the impact and explore the effects of the head form shape through a three-dimensional finite element model. To properly analyze the problem, the history time of the mechanical responses, such as impact forces, bending, principal, and residual stresses, are highlighted and assessed. Additionally, a comparison with the experimental data found in the literature was performed to check the validity and accuracy of the considered finite element model. The damage occurring in the T700/Epoxy plates is illustrated for each impactor head shape. The mechanical response curves and all kinds of damage of the presented simulations are in perfect agreement with the experiments. The proposed VUMAT is efficient in the prediction of fiber kinking, matrix cracking, fiber splitting, and fiber tension of a laminate, and more importantly, it is easy to implement for other types of materials and the reproducibility of the analysis is assured.

Damage Detection in Free–Free Glass Fiber Fabric Composite Beams by measuring Flexural and Longitudinal Vibrations

“…Important parameters of the impact events are the peak impact forces and bending, the duration of the impact event, the stresses and strains and the shape of the contact zone [21], which need to be additionally analyzed. Further research should be performed to quantify the defect position by modal shape analysis and to investigate other types of defects and the anisotropy caused by the location of glass layers in composite beams.…”

“…Impulse excitation is a popular technique for the diagnosis of various materials [20]. In [21], it is shown that the shape of the impactor head is an essential parameter on the low-velocity impact. The damage occurring in the composite plates is illustrated and analyzed for hemispherical and flat head shape hammer [21].…”

“…In [21], it is shown that the shape of the impactor head is an essential parameter on the low-velocity impact. The damage occurring in the composite plates is illustrated and analyzed for hemispherical and flat head shape hammer [21]. The earliest research on the subject analyzed natural frequencies; however, due to measurement errors and noise, natural frequencies in such mode shapes are not sensitive to structural damage [1,6,11].…”

Experimental and Numerical Investigation on Damage Resistance Characteristics of Woven E-Glass/Epoxy Composite Laminates Subjected to Drop-Weight Impacts

“…Better impact resistance was observed in laminates that had a higher areal density and more layers of nickel-coated carbon fiber veils, which resulted in a higher impact force and smaller damage area [14]. The shape of the impactor has a considerable effect on the extent of damage induced in composite laminates during impacts at low velocity [15]. A considerable reduction in computational costs was achieved by implementing the mass-scaling method in the numerical analysis of the impact response of semicylindrical woven composite shells [16].…”