Experimental Study on the Stitching Reinforcement of Composite Member with a Circular Hole

2010 ◽  
Vol 152-153 ◽  
pp. 459-464
Author(s):  
Xi Ping Zhu ◽  
Zhang Xin Guo ◽  
Xiao Ang Cao ◽  
Xi Zhe Zhi
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Circular Hole ◽  
Composite Laminates ◽  
Strain Distribution ◽  
Row Spacing ◽  
Loading Direction ◽  
Edge Distance ◽  
Edge Location ◽  
Strength And Stiffness

Experiment studies are carried out on the stitching reinforcement of composite laminates containing a circular hole. The tensile strength and stiffness are measured, and their dependence on stitching parameters such as stitching needle distance, row spacing, edge distance and stitching type (i.e. single stitching or double stitching) are analyzed. The strain distribution is investigated experimentally for different stitching parameters, external load and edge location of the hole. It is shown that the results of stitching reinforcement are quite different for composite laminates with a circular hole, which could provide proper stitching parameters for designers. The analysis for different failure samples are made. Reinforced by stitching, the failure section is mainly perpendicular to loading direction. It can be seen that the capacity of load bearing rises when the composite components are reinforced by stitching the hole.

Experimental Study on Bond Behavior between CFRP Sheet and Wood

2011 ◽  
Vol 368-373 ◽  
pp. 2314-2318
Author(s):  
Qi Fang Xie ◽  
Jian Yang Xue ◽  
Hong Tie Zhao ◽  
Jun Fang Hu
Keyword(s):  
Experimental Study ◽  
Bond Length ◽  
Strain Distribution ◽  
Fiber Reinforced Polymer ◽  
Engineering Practice ◽  
Bond Behavior ◽  
Cfrp Sheets ◽  
Reinforced Polymer ◽  
Cfrp Sheet ◽  
Edge Location

Fiber-reinforced polymer (FRP) has been applied to reinforce wood structure with its many advantages. But results of experimental study and engineering practice have showed that the failure is generally caused for lack of bong strength between FRP and wood, so the bond behavior between FRP and wood is very important. In this paper, based on the shear bond experiment between wood and CFRP sheet, the bond properties are researched such as failure character, characteristic of strain distribution, effective bond length and bond strength. Results showed that: at the loaded-end, the strain of the CFRP sheets is the maximum, and then strains decrease quickly with the increase in distance from the loaded-end. Strain distribution along cross direction is not uniform and the strains of the center location are bigger obviously than that of the edge location. The effective bond length between CFRP sheet and wood is more than 120mm.

Influence of patch length and thickness on strength and stiffness of patched laminates

2017 ◽  
Vol 52 (16) ◽  
pp. 2199-2212 ◽  
Author(s):  
Bernhard Horn ◽  
Johannes Neumayer ◽  
Klaus Drechsler
Keyword(s):  
Tensile Strength ◽  
Composite Laminates ◽  
Three Dimensional ◽  
Minor Effect ◽  
Stiffness Properties ◽  
Additional Testing ◽  
Strength And Stiffness ◽  
Cohesive Zone Elements ◽  
A Minor ◽  
Patch Length

Composite laminates made of fiber patches offer a large flexibility in terms of layup design. Geometrical layup parameters such as patch length and patch thickness are unique for this type of laminates. This article presents results on the investigation of the influence of patch length and patch thickness on the tensile strength and stiffness properties of patched laminates to contribute to the material understanding. The results show that an increasing of patch thickness leads to a drastic reduction in tensile strength of up to 48.7% for a triplication in patch thickness. The patch length was varied between 20 and 120 mm. Up to 60 mm, the tensile strength increased by 11.5%, further increase did not contribute to a further improved tensile strength. The influence of patch length and patch thickness on the stiffness was found to have only a minor effect. A three-dimensional numerical model that accounts for delamination failure using cohesive zone elements shows very good correlation with the experimental results. This shows its potential for virtual testing to determine tensile strength and stiffness properties of patched laminates without additional testing effort.

EFFECT OF HYBRIDIZATION ON OPEN-HOLE TENSION PROPERTIES OF WOVEN KEVLAR/GLASS FIBER HYBRID COMPOSITE LAMINATES

2015 ◽  
Vol 76 (9) ◽  
Author(s):  
Norazean Shaari ◽  
Aidah Jumahat ◽  
Shahrul Azam Abdullah ◽  
Ahmad Zariff Hadderi
Keyword(s):  
Tensile Strength ◽  
Glass Fiber ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Open Hole ◽  
Strength And Stiffness

Hybrid laminates consisting of woven Kevlar/glass fiber composite plies were studied in terms of their residual tensile strength, stiffness and fracture surface.  Residual tensile strength and stiffness were determined from the open hole tension test according to ASTM D5766. The laminates of Kevlar fiber reinforced polymer (KFRP), glass fiber reinforced polymer (GFRP) and hybrid of Kevlar-glass fiber reinforced polymer (KGFRP) were fabricated using a vacuum bagging process. Three different ratios of Kevlar to glass fiber plies were prepared in this study which were 20:80, 50:50, and 80:20. Results showed that hybrid laminate consisting of 80:20 Kevlar to glass fiber plies, produced higher residual tensile strength and stiffness when compared to the other hybrid system. Furthermore, strength and stiffness of hole specimens were reduced within 50-63% when compared to unhole specimens due to existence of the hole. In addition, the effect of adding nanosilica to the hybrid system was also studied. 5 wt% of nanosilica was added to the hybrid composite laminates and results showed that higher tensile strength and stiffness was observed in GFRP and 20:80 KGFRP specimens, while the tensile strength was decreased with an increased number of Kevlar fiber. This research was conducted as there are limited number of studies that have been done on the tensile strength of woven hybrid composite laminates so far, especially on hybridization of Kevlar and glass fiber with consideration on the effect of hole and addition of nanofillers.

scholarly journals Tensile behavior of a Brazilian Disk Containing non-persistent Joint Sets Subjected to Diametral Loading: An Experimental Investigation

2021 ◽  
Author(s):  
Mostafa Asadizadeh ◽  
Jamshid Shakeri ◽  
Nima Babanouri ◽  
Mohammad Rezaei
Keyword(s):  
Tensile Strength ◽  
Tensile Stress ◽  
Failure Pattern ◽  
Structural Defects ◽  
Joint Spacing ◽  
Joint Continuity ◽  
Failure Patterns ◽  
Loading Direction ◽  
Joint Parameters ◽  
Strength And Stiffness

Abstract Structural defects are part of the inherent characteristics of rock masses. They can be found in the form of fishers, joints, and beddings and can be divided into persistent or non-persistent one. The coalescence of non-persistent cracks may lead to the formation of persistent joints under the tensile stress field, leading to instability of rock mass. The mechanical behavior of non-persistent jointed disks under tensile stress has essential implications for rock engineering structures. In this paper, concrete Brazilian disks containing open non-persistent joints were constructed and subjected to diametral loading to investigate the effect of this kind of joint parameters on the tensile strength and stiffness of disks. The effect of some parameters, such as joint continuity factor (the relationship between joint length and rock bridge length), bridge angle, joint spacing, and loading direction with respect to joint angle were investigated to estimate the tensile strength and stiffness as well as failure pattern. The results of experiments revealed that the tensile strength, stiffness, and failure pattern of Brazilian disks are highly affected by non-persistent pre-existing crack parameters. The increase of joint continuity factor and loading direction leads to an increase in tensile strength and a decrease in stiffness. However, when bridge angle and spacing increase tensile strength rises, and the former decreases stiffness while the latter results in its reduction. Finally, all the parameters significantly affect the failure pattern, and some failure patterns such as step-path failure, splitting, or sliding may occur as a function of non-persistent joint parameters.

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