Multi-holes configurations of woven fabric kenaf composite plates: experimental works and 2-D modelling

Abstract

A study on structures response in multi-holes plates is important to understand the effect of neighbouring hole on stress concentration as subjected to tensile loading prior to bearing failure in multi-bolted joints. Current work implemented experimental framework on staggered and non-staggered multi-holes configurations to include various lay-up types, plate thickness and hole configurations as specified in the testing series. Experimental observations found that all configurations failed in net-section path suggesting that fracture initiates and propagates from the notch tip perpendicular to loading direction in self-similar fashion through the plate thickness. Non-staggered hole configurations demonstrated peak load compared to staggered counterparts due to more congested holes in staggered configurations. Two-dimensional Extended Finite Element Method (XFEM) modelling framework was carried out in all configurations investigated by sufficient meshing refinements, damage stabilization value and boundary conditions. XFEM was extended from classical finite element expression which has enriched function to enable the crack be tracked visually. A physically-based constitutive model from traction-separation relationship was applied and independently measured material properties and in-plane elastic properties were implemented in current work. Strength prediction results showed that good agreement was found in all testing series and showed discrepancies of less than 15%, the best prediction in combination of PX4 lay-ups and staggered multi-holes configurations series.

XFEM Modelling in Multi-bolted Joints Using a Unified Bolt Preload

“…Nevertheless, non-staggered configurations exhibited better prediction than staggered counterparts due to less contact interactions, less bearing area and not much complex stress distributions exhibited. Similar findings were reported in multi-holes configurations (Supar and Ahmad, 2018b) and multi-bolts configurations (Supar and Ahmad, 2018a) where more complex stress distribution may exhibit within each bolt in diagonal directions. From stress analysis study of these testing series (Supar and Ahmad, 2018c), staggered hole configurations give highest tangential stress, σT along hole boundary than non-staggered configuration due to resistance stress diagonally may not be physically represented in current framework of using smeared-out properties.…”

Application of Bilinear Softening Laws and Fracture Toughness of Foamed Concrete

“…Similar findings with global mesh size 2 were also reported by [46], while investigations by [47][48][49] involved global meshes with sizes of 0.01 mm, 0.125 mm, and between 0.5-1 mm, respectively. Meanwhile, a damage stabilization cohesive with a value of 1 × 10 −5 was also reported in [28,50,51].…”

Failure study of the woven composite material: 2.5 D carbon fabric/ resin epoxy

“…In order to conduct a failure simulation of the composite G1151/Resin epoxy, a simple coupon simulation test has been carried out, the present method was carried out by several authors [32][33][34]. The dimensions of the composite virtual coupon were 20 x10 x 1 mm, which represent a small volume of the material under uniaxial stress.…”

“…Also several authors [25][26][27][28][29][30][31][32] estimate the macro woven fabric composite behaviour as elastic. The behaviour could be written as follow, Equation 12-17: ( Then the analytic elastic properties of the macro scale behaviour of the woven fabric G1151/Resin Epoxy could be calculated and are listed in the…”