Failure of Composite T-Joints in Bending with Through-the-Thickness Reinforcement: Stitching Vs Z-Pinning

2012 ◽  
Vol 525-526 ◽  
pp. 233-236 ◽  
Author(s):  
H. Cui ◽  
Yu Long Li
Keyword(s):  
Energy Absorption ◽  
Present Model ◽  
Failure Process ◽  
Maximum Load ◽  
T Joints ◽  
Pull Out ◽  
Simple Theoretical Model ◽  
Bending Load ◽  
Delamination Resistance ◽  
Mode I Delamination

The stitched composite T-joints and Z-pinned ones subject to bending load were investigated in this paper. A simple theoretical model characterizing the failure process of through the thickness reinforcement (TTR) during mode I delamination was presented. The experimental results showed that the initial damage load and maximum load of stitched specimens are higher than that of Z-pinned ones, while the energy absorption of stitched specimens during delamination is lower than that of Z-pinned ones. The energy absorption values predicted by the present model meet the experiments reasonably well. High friction force at the interface between TTR tow and matrix, with a long pull-out displacement of the tow, helps to improve the delamination resistance.

scholarly journals Fatigue behaviour of fibre-reinforced composite T-joints

2018 ◽  
Vol 165 ◽  
pp. 07004
Author(s):  
Ying Wang ◽  
Constantinos Soutis
Keyword(s):  
Fatigue Life ◽  
Testing Machine ◽  
Fatigue Loading ◽  
Maximum Load ◽  
Fatigue Behaviour ◽  
Control Mode ◽  
Static Properties ◽  
T Joints ◽  
Pull Out ◽  
Reinforced Composite

In this paper a study was carried out on the fatigue life of fibre-reinforced composite T-joints subjected to a tensile pull-out loading. The composite T-joints have been made of glass fabric infused with epoxy resin using a vacuum assisted resin transfer moulding technique. Methods such as the use of veil layers, tufting techniques and 3D weave have been employed to improve the interlaminar fracture toughness of the composite T-joints. All the tests were conducted in an Instron testing machine using a specially designed test fixture. Fatigue tests were performed in a load control mode with a stress ratio of R = σmin/σmax = 0.1. The cyclic loading pattern was a sinusoidal wave with a frequency of 6 Hz. The specimens were cycled at a series of constant maximum load values up to failure. Fatigue loads versus life data for each T-joint type were produced at various maximum applied loads. The 3D weave T-joints were found to have the best performance in both static and fatigue loading. Increasing the static properties increases fatigue life performance; the increasing rate in fatigue life is changed with the number of stress cycles. The location for the through-thickness reinforcement plays an important role in improving fatigue life of the Tjoints. Fatigue life is significantly improved if the web is reinforced in through-thickness direction. A finite element (FE) failure model was also created using ABAQUS to determine the location where delamination is initiated and its subsequent propagation.

Study on Tensile Mechanical Behavior of Composite T-Joints

2017 ◽  
Vol 1142 ◽  
pp. 146-151
Author(s):  
Zhi Lin Liu ◽  
Pu Rong Jia ◽  
Tao Peng ◽  
Zheng Lan Yao
Keyword(s):  
Tensile Strength ◽  
Composite Laminates ◽  
Failure Process ◽  
Load Condition ◽  
Maximum Load ◽  
Displacement Curve ◽  
Test Results ◽  
Reinforcement Effect ◽  
T Joints ◽  
Pin Reinforcement

Based on three kinds of composite T-joints with different connection way for tension test outside the plane, it was obtained contrastively that how the ordinary adhesive, Z-pin reinforcement and stitching reinforcement three different fitting influence tensile strength, damage failure process and failure mode of composite T-joints. The test results showed that compared with ordinary adhesive connection mode, tensile strength of the Z-pin reinforcement and stitching reinforcement T-joints increased by 13.6% and 11.4%, respectively; and the largest deformation increased by 19.2% and 15.1%, respectively. After reaching maximum load condition, the ordinary adhesive T-joints had brittle failures, but Z-pin reinforcement and stitching reinforcement T-joints all showed that the ductile damage behavior, corresponding to the load-displacement curve appeared saw-tooth wave platform. Obviously, the Z-pin reinforcement T-joints had the most significant reinforcement effect on tensile properties of composite laminates T-joints.

Experimental Analysis of Aluminum Alloy Section Bars and their Mortise and Tenon Joints under Bending Load

2011 ◽  
Vol 415-417 ◽  
pp. 2338-2344
Author(s):  
Xin Shen Huang ◽  
Qun Gao ◽  
Zhi Jian Zong
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Energy Absorption ◽  
Experimental Analysis ◽  
Absorption Capacity ◽  
Main Section ◽  
Bending Properties ◽  
Energy Absorption Capacity ◽  
Bending Load ◽  
Mortise And Tenon

Different laid modes of aluminum alloy section bars and their mortise and tenon joints were bending tested, and their mechanical properties were compared, in order to research on the influence that forming a mortise and tenon joint brought to the original bars. Opening a hole laterally and inserting another shorter bar in the hole changed the bending properties and energy absorption capacity of the original bar. In horizontal laid mode, the mortise and tenon joint was weaker than the original bar when bearing bending load, but it was stronger in vertical laid mode. Weld beads of the mortise and tenon joints were strong enough to maintain the structure integrality before the main section bars were destroyed by load.

scholarly journals Experimental and Simulation Investigation of Bending Moment Effect on Hollow Columns of Multi-layers of Hybrid Materials

2019 ◽  
Vol 12 (1) ◽  
pp. 44-55
Author(s):  
Ayad A. Ramadhan
Keyword(s):  
Hybrid Materials ◽  
Volume Fraction ◽  
Load Capacity ◽  
Testing Machine ◽  
Bending Moment ◽  
Maximum Load ◽  
Experimental Procedure ◽  
Bending Load ◽  
Alumina Composite ◽  
Moment Effect

This paper presented the effect of bending on multi-layer of hollow columns of Hybrid materials (Carbon-Glass /epoxy-Alumina) composite this effect occurred and volume fraction of fibers. An experimental procedure was developed to study the performance of these effects under bending load using a hydraulic bending device type (MATEST. SRL) testing machine. This study has three forms through the selection of columns hollows width to thickness (a/b) (0.5, 1 and 2) with three types of layers of samples (2,4 and8) layers. The ultimate load of failure for each Hybrid/epoxy-Al2O3 had been determined and specified the optimum volume fraction (Vf) due to the effect of mixing 50% and 60% were low in the case for compared 55% volume fraction. To simulate this problem the researcher used Explicit Mesh for AUTODYN under ANSYS-15 software, it was found that maximum bending load for Hybrid/ Epoxy-Al2O3 Specimens, the maximum load of specimens increased with increasing number of layers from 2L to 8L. The results also identified that the maximum load capacity by 55% volume fraction and a/b=0.5 of all composite specimens was highest from the others types of (50% and 60%) volume fractions and (a/b=1 and a/b=2) .Also, the Increasing ratio of stress capacity for specimens have 4 to 2 layers (4/2)  and 8 to 4  (8/4) for experimental results have maximum value with increasing by 48.19%  and 46.84% at (Sp.4#8/Sp.2#4) and (Sp.8#6/Sp.4#6) respectively.

Strength of Composite T-Joints under Pull-Out Loads

1997 ◽  
Vol 16 (6) ◽  
pp. 503-518 ◽  
Author(s):  
Efstathios E. Theotokoglou
Keyword(s):  
T Joints ◽  
Pull Out

Steel Fibre Performance in Concrete with Expansive Additives under Restrained Hardening Conditions

2018 ◽  
Vol 788 ◽  
pp. 30-35
Author(s):  
Arturs Lukasenoks ◽  
Rolands Cepuritis
Keyword(s):  
Compressive Strength ◽  
Steel Fibre ◽  
Single Fibre ◽  
Steel Shell ◽  
Concrete Compressive Strength ◽  
Flexural Behaviour ◽  
Pull Out ◽  
Delamination Resistance ◽  
Expansive Additive ◽  
Standard Steel

Steel moulds in the form of a rigid cubical shell were developed in order to investigate single steel fibre pull-out resistance in concrete with expansive additive under restrained hardening conditions. The cubical shell (100 x 100 x 100 mm) with wall thickness of 5 mm was designed with two openings – a small 4 mm hole for fibre embedment in concrete and a larger opening for filling the concrete. Standard beam (100 x 100 x 400 mm) and cube (150 x 150 x 150 mm) samples were also manufactured and hardened under and without restrained conditions, where the restraint was realised by rigid standard steel moulds. All the restrained conditions realized by either the developed cubical steel shell (for single fibre pull-out) or existing beam and cube moulds simulate internal (from steel fibres in concrete) and external (from friction against sub-base) restraints that hinder expansion of the concrete due to the use of special expansive additives in a flooring slab structure installed on ground. Samples with a single hooked-end steel fibre (50 mm long and 0.75 mm in diameter), with and without expansive additive were manufactured and tested in the developed mould geometry. The results show that restrained expansion in concrete with expansive additives positively affects concrete compressive strength, single fibre pull-out and flexural behaviour. Concrete compressive strength increases by 7.5 %, single fibre delamination resistance increases by 24 %, the peak pull-out load by 10.8 % while the flexural strength increases by 3.1 %.

scholarly journals Flax, Basalt, E-Glass FRP and Their Hybrid FRP Strengthened Wood Beams: An Experimental Study

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1255 ◽  
Author(s):  
Wang ◽  
Bachtiar ◽  
Yan ◽  
Kasal ◽  
Fiore
Keyword(s):  
Failure Modes ◽  
Maximum Load ◽  
Tensile Failure ◽  
Flexural Behavior ◽  
Single Type ◽  
Small Scale ◽  
Frp Composites ◽  
Bending Load ◽  
Wood Beams ◽  
Glass Frp

In this study, the structural behavior of small-scale wood beams externally strengthened with various fiber strengthened polymer (FRP) composites (i.e., flax FRP (FFRP), basalt FRP (BFRP), E-glass FRP (“E” stands for electrical resistance, GFRP) and their hybrid FRP composites (HFRP) with different fiber configurations) were investigated. FRP strengthened wood specimens were tested under bending and the effects of different fiber materials, thicknesses and the layer arrangements of the FRP on the flexural behavior of strengthened wood beams were discussed. The beams strengthened with flax FRP showed a higher flexural loading capacity in comparison to the beams with basalt FRP. Flax FRP provided a comparable enhancement in the maximum load with beams strengthened with glass FRP at the same number of FRP layers. In addition, all the hybrid FRPs (i.e., a combination of flax, basalt and E-glass FRP) in this study exhibited no significant enhancement in load carrying capacity but larger maximum deflection than the single type of FRP composite. It was also found that the failure modes of FRP strengthened beams changed from tensile failure to FRP debonding as their maximum bending load increased.

scholarly journals Mechanical Behavior of Entangled Metallic Wire Materials under Quasi-Static and Impact Loading

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3392 ◽  
Author(s):  
Yiwan Wu ◽  
Lei Jiang ◽  
Hongbai Bai ◽  
Chunhong Lu ◽  
Shangzhou Li
Keyword(s):  
Energy Absorption ◽  
Impact Loading ◽  
Absorption Rate ◽  
Maximum Load ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Metallic Wire ◽  
Maximum Deformation ◽  
Air Damping ◽  
Stiffness And Damping

In this paper, the stiffness and damping property of entangled metallic wire materials (EMWM) under quasi-static and low-velocity impact loading were investigated. The results reveal that the maximum deformation of the EMWM mainly depends on the maximum load it bears, and that air damping is the main way to dissipate impact energy. The EMWM can absorb more energy (energy absorption rate is over 60%) under impact conditions. The EMWM has excellent characteristics of repetitive energy absorption.

PULL OUT STRENGTH FOR DIFFERENT SIZE OF DOWEL AND GRAIN DIRECTION OF GLULAM

2016 ◽  
Vol 78 (5-4) ◽  
Author(s):  
Tengku Anita Raja Hussin ◽  
Mohamad Iswandi Jinne ◽  
Rohana Hassan
Keyword(s):  
Failure Modes ◽  
Maximum Load ◽  
Experimental Program ◽  
Drilling Process ◽  
Test Results ◽  
Bond Behaviour ◽  
Pull Out ◽  
Timber Joints ◽  
Different Thickness ◽  
Pull Out Strength

This paper presents an experimental program for testing glued-in dowel glulam timber joints. Hundred thirty glulam specimens, each with a single glued-in rebar parallel to the grain and perpendicular to grain with different size of dowels 12mm, 16mm and 20mm were tested to evaluate the effects of anchorage length and different dowel diameter for parallel and perpendicular to the grain on pull-out strength and bond behaviour of glued-in rebar timber joints. The test results showed that the maximum load for specimen with dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction. Failure modes were characterized by pull out failure in the mode of adhesive-dowel, yet one sample failed in timber-adhesive mode. This might happened because the surface of the timber was burned by drilling machine during the drilling process. The pull-out was tested with different thickness grain direction with different dowel size with a rate of 2mm/min and the failure modes were observed after the testing of pull-out test. PRF is the adhesive used for the strengthening purposes. Resistance to the withdrawal of dowels glued-in perpendicularly was 44.2% to 53.5 % lower than that obtained for dowels glued-in parallel to the grain direction. The result shows that the dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction.

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