scholarly journals Effect of nanoclay (Kaolinite) on mechanical properties of epoxy-fiber composite

2020 ◽  
Vol 12 (01) ◽  
pp. 38-43
Author(s):  
Hisham M Hasan ◽  
◽  
Ahmed R Majeed ◽  
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Shear Strength ◽  
Tensile Test ◽  
Carbon Fibers ◽  
Epoxy Matrix ◽  
Interfacial Shear Strength ◽  
Fiber Composite ◽  
Weight Fraction ◽  
Interfacial Shear

An experimental investigation using drag-out tensile test to calculate the interfacial shear strength for different embedded lengths of Kevlar and carbon fibers reinforced epoxy matrix with nanoclay (kaolinite) for different ratio weight, the interfacial shear strength increased by with increasing of embedded length and ratio weight fraction of nanoclay that adding to epoxy matrix.

Size Effect on Microbond Testing Interfacial Shear Strength of Fiber-Reinforced Composites

2019 ◽  
Vol 86 (7) ◽  
Author(s):  
Qiyang Li ◽  
Guodong Nian ◽  
Weiming Tao ◽  
Shaoxing Qu
Keyword(s):  
Shear Strength ◽  
Carbon Fiber ◽  
Size Effect ◽  
Epoxy Matrix ◽  
Interfacial Shear Strength ◽  
Interfacial Shear ◽  
Experimental Results ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Material Systems

Microbond tests have been widely used for studying the interfacial mechanical properties of fiber-reinforced composites. However, experimental results reveal that the interfacial shear strength (IFSS) depends on the length of microdroplet-embedded fiber (le). Thus, it is essential to provide an insight into this size effect on IFSS. In this paper, microbond tests are conducted for two kinds of widely used composites, i.e., glass fiber/epoxy matrix and carbon fiber/epoxy matrix. The lengths of microdroplet-embedded glass fiber and carbon fiber are in the ranges from 114.29 µm to 557.14 µm and from 63.78 µm to 157.45 µm, respectively. We analyze the representative force–displacement curves, the processes of interfacial failure and frictional sliding, and the maximum force and the frictional force as functions of le. Experimental results show that IFSS of both material systems monotonically decreases with le and then approaches a constant value. The finite element model is used to analyze the size effect on IFSS and interfacial failure behaviors. For both material systems, IFSS predicted from simulations is consistent with that obtained from experiments. Moreover, by analyzing the shear stress distribution, a transition of interface debonding is found from more or less uniform separation to crack propagation when le increases. This study reveals the mechanism of size effect in microbond tests, serving as an effective method to evaluate the experimental results and is critical to guidelines for the design and optimization of advanced composites.

scholarly journals Study on the Static Performance of Prefabricated UHPC-Steel Epoxy Bonding Interface

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yang Zou ◽  
Jinlong Jiang ◽  
Zhixiang Zhou ◽  
Xifeng Wang ◽  
Jincen Guo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Shear Strength ◽  
Shear Test ◽  
Interfacial Shear Strength ◽  
Interfacial Shear ◽  
Bonding Interface ◽  
Tensile Shear ◽  
Epoxy Bonding ◽  
Shear Coupling

Prefabricated UHPC-steel composite structure can make full use of the two materials’ mechanical and construction performance characteristics, with super mechanical properties and durability, which has been proved to be a very promising structure. However, using traditional mechanical connectors to connect prefabricated UHPC and steel not only is inconvenient for the prefabrication of UHPC components but also introduces heavy welding work, which is detrimental to the construction speed and antifatigue performance of the composite structure. Bonding UHPC-steel interface with epoxy adhesive is a potential alternative to avoid the above problem. In order to explore the mechanical properties of the prefabricated UHPC-steel epoxy bonding interface, this study carried out the direct shear test, tensile test, and tensile-shear test of the UHPC-steel epoxy-bonded interface (prefabricated UHPC-steel epoxy bonding interface). The results show that the interface failure is mainly manifested as the peeling of the epoxy-UHPC interface and the destruction of part of the UHPC matrix (the failure of the UHPC's surface). In pure shear and pure tension state, the interfacial shear strength is 5.14 MPa and the interfacial tensile strength is 1.18 MPa. In the tensile-shear state, the interfacial shear strength is 0.61 MPa and the interfacial tensile strength is 1.06 MPa. The stress-displacement curves of the interface normal and tangential direction are all in the shape of a two-fold line. The ultimate displacement was within 0.1 mm, showing the characteristics of brittle failure. Finally, a numerical model of the tensile specimen is established based on the cohesive interface element, and the interfacial tensile-shear coupling failure mechanism (tensile-shear coupling effect) is analyzed.

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