Notched Strength and Fracture Criterion in Fabric Composite Plates Containing a Circular Hole

Abstract

The effects of the hole size and the specimen width on the fracture behavior of several woven fabric composite plates are experimentally investigated in tension. It is shown in this paper that the characteristic length ( d o) in the Point Stress Criterion (PSC) depends on the hole size and the specimen width. A modified PSC for predicting the notched strength is proposed. An excellent agreement is found between the experimental results and the analytical predictions using the modified PSC. When the unstable fracture occurred, the equivalent critical crack length ( a c) corresponding to the damage zone size is about twice the characteristic length. The characteristic length decreases with an increase in the notched strength. The critical energy release rate ( G c) corresponding to the unstable fracture criterion is independent of the hole size for the same specimen width. G c increases with an increase in the specimen width. These results can be explained by the correlation between the G c and the notch sensitivity factor (k).

Physically based finite element strength prediction in notched woven laminates under quasi-static loading

“…Although the opaque nature of the CFRP means that direct observations of damage are less straightforward, there was evidence of tow failure before specimen failure. Other valuable data concerning notched tensile strength of woven composites had been presented previously by Kim et al 7 More recent work by Zahari et al 8 has considered the notched compressive behaviour of woven GFRP.…”

“…1), reducing computational cost and time during the processing stage. The first data set is taken from the extensive experimental work conducted by Kim et al 7 using three types of woven fabric composite systems with various combinations of notch sizes, laminate width and volume fraction. All plates have a length L of 200 mm with varying widths W and a circular hole of diameter d of 5 mm.…”

“…A limitation of the previous studies is that the material parameters within the models have generally been calibrated against experimental data rather than determined independently. Here we use independent measurements of unnotched strength and toughness, where available, to develop numerical models for the experimental studies on woven fabric systems conducted by Kim et al using GFRP 7 and Belmonte et al using GFRP 5 and CFRP. 6 In the next section, details of the numerical procedure are provided.…”

Strength Prediction of Notched Woven Composite Plates Using a Cohesive Zone Approach

“…Although the opaque nature of the CFRP means that direct observations of damage are less straightforward, there was evidence of tow failure before specimen failure. Other valuable data concerning notched strength of woven composites are presented in the papers by Kim and Kim, (1995).…”

Finite Element Based Point Stress Criterion for Predicting the Notched Strengths of Composite Plates

“…They were then modified into three parameter models based on experimental evidence [5,6]. These criteria can be extended to include any laminate of symmetric construction by using the anisotropic plate solution discussed by Lekhnitskii [4] Traditionally, analytical solutions [15][16][17] were required in predicting the notched strengths of composite plates, as a result both PSC and ASC were only applied for predicting the notched strengths of composite plates each with a center hole [18][19][20][21][22][23][24][25], which may be either circular or elliptic. Therefore, to predict the notched strengths of composite plates each with arbitrary shape of notch located either at the edge or in the center of the plate by both PSC and ASC is still out of reach up to now.…”