Behavior of Pin-loaded Laminated Composites

Abstract

In this study, an investigation was carried out to determine the effects of joint geometry and fiber orientation on the failure strength and failure mode in a pinned joint laminated composite plate. Behavior of pin-loaded laminated composites with different stacking sequence and different dimensions has been observed experimentally. E/glass-epoxy composites were manufactured to fabricate the specimens. Mechanical properties of the composites were characterized under tension, compression and in-plane shear in static loading conditions. Laminated composites were loaded through pins. Single-hole pin-loaded specimens were tested for their tensile response and width-tohole diameter (W/D) and edge distance-to-hole diameter (E/D) ratios evaluated. A series of experiments was performed with six different material configurations ([0/T45] s -[90/T45] s , [0/90/0] s -[90/0/90] s and [90/ 0] 2s -[T45] 2s ), in all, over 120 specimens. E/D ratios and W/D ratios of plates were changed from 1 to 5 and 2 to 5, respectively. Failure propagation and failure type were observed on the specimens. The influence of the joint geometry on the strength of the pin-loaded composites was assessed. When laminated composite plates were loaded to final failure, three basic failure modes consisting of net-tension, shear out and bearing failure were observed for the different geometric dimensions. All the connections tested showed that the fiber orientations have a definite influence on the position around hole circumference at which failure initiated. Net-tension failure occurred for specimens that had small width and large end distance. When the width was increased, the specimens which had small end distances failed in the shear-out modes. When the end distance was increased, bearing failure developed in addition to shear-out failure. The experimental results showed that the ultimate load capacities of E/glassepoxy laminate plates with pin connection were increased by increasing W and E. However, increasing the E/D and W/D ratios beyond a critical value has an insignificant effect on the ultimate load capacity of the connection.

Effect of Ply Orientation on Strength and Failure Mode of Pin Jointed Unidirectional Glass-epoxy Nanoclay Laminates

“…Acetone is an important solvent with molecular formula (C 3 H) 2 CO and has been used to properly mix epoxy and nanoclay. It was supplied by the loba Chemie Pvt.…”

“…For the design and assembly of the different structures holes are to be drilled. The stress concentration around the hole causes the unpredictable failure and results in poor performance of the joint 2 . Joint design and their efficiency are the major concern in the fiber reinforced laminate composites used for a structure.…”

“…Okutan 7 9 , et al observed the behaviors of pin loaded woven glass-vinylester composite plate with various dimensions both experimentally and numerically. Baba 2 investigated the effects of varying ratios of width-to hole diameter and edge distance-to-hole diameter and fiber orientation on the failure strength and failure mode in a pinned joint laminated composite plate. Karakuzu 10 , et al determined the failure mode, failure load and bearing strength in woven glass vinylester composite plates with two parallel circular holes.…”

Dosage optimization and bolted connections for UHPFRC ties

“…Some of them are isotropic, as the steel [199], the ferrocement [101], the resin-based composites, the aluminum or the plastic. Others are anisotropic, as the laminated composites [177], the fiber reinforced materials or the timber composites [168], which strength depends on the grain direction. The UHPFRC, as a fiber reinforced composite, has also anisotropic properties, providing better tensile response when the fibers are aligned on the direction of the tensile efforts.…”

“…Normally it crosses the hole, as its section is the one with the most reduced area. In tests performed to materials as wood or laminated composites load drops to zero at maximum load [168], showing a brittle failure. At figures 5.7 and 5.8 this failure is exposed for shells made of different materials.…”