scholarly journals Failure Characteristics of Carbon/BMI Sandwich Composite Joint under Pull-out Loading

2017 ◽  
Vol 30 (2) ◽  
pp. 132-137
Author(s):  
Gyeong-Chan Lee ◽  
Young-Ho Choi ◽  
Kowan-Woo Lee ◽  
Jae-Hoon Sim ◽  
Young-In Jung
Keyword(s):  
Sandwich Composite ◽  
Failure Characteristics ◽  
Pull Out ◽  
Composite Joint

Experimental characterization of Mode II fatigue delamination growth onset in composite Joints

2021 ◽  
pp. 002199832110567
Author(s):  
Felipe P Garpelli ◽  
Francis M González Ramírez ◽  
Rita de Cássia M Sales ◽  
Mariano A Arbelo ◽  
Marcos Y Shiino ◽  
...  
Keyword(s):  
Failure Process ◽  
Strain Energy Release ◽  
Fatigue Loading ◽  
Mode Ii ◽  
Adhesive Failure ◽  
Cohesive Failure ◽  
Delamination Growth ◽  
Pull Out ◽  
Composite Joint ◽  
Bonded Composite

In this article, the structural behavior of co-cured composite joint (CC), co-bonded composite joint (CB), and secondary-bonded composite joint (SB) under Mode II fatigue loading was evaluated. Fatigue performance was evaluated in sub-critical strain energy release rate (SERR) associated with Mode II fatigue induced delamination growth onset. Fatigue tests were carried out using the three-point bending End Notched Flexure test setup for different energy ratios. The experimental results are presented in terms of SERR versus number of cycles, and the SERR threshold for no growth is determined (Gth). Fractographic analyses were performed in order to identify the main failure mechanisms related to each joining technology under Mode II. The results indicated an initial cohesive failure followed by an adhesive failure promoted by crack propagation at the interface between the adhesive and the composite adherend on SB and CB samples, through the coalescence of microcracks that promote the adhesive failure process, leading to fiber pull-out from the matrix and cusps formation in the fracture surface. These results explain the low performance behavior observed on SB and CB bonded techniques. It is worth mentioning that the results and behavior observed in this work are valid only for the laminates, adhesives, surface treatment, and environmental conditions tested herein.

scholarly journals Experimental and Finite Element Research on the Failure Mechanism of C/C Composite Joint Structures under Out-of-Plane Loading

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2922
Author(s):  
Yanfeng Zhang ◽  
Zhengong Zhou ◽  
Zhiyong Tan
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Displacement Curve ◽  
Finite Element Software ◽  
Pull Out ◽  
Composite Joint ◽  
Element Simulation ◽  
Out Of Plane ◽  
The Matrix ◽  
Failure Morphology

The loading and the failure mode of metal hexagon bolt joints and metal counter-sunk bolt joints of C/C composites were investigated. The joints were tested for out-of-plane loading at two temperatures (600 °C and 800 °C). The failure morphology of a lap plate was investigated, and the main failure modes were determined. The typical load–displacement curve was characterized and the test was simulated using ABAQUS non-linear finite element software. Furthermore, progressive damage was induced, and comparison of the finite element simulation with the experimental data revealed that the failures mainly occurred in the lower lap plate and were dominated by cracking and delamination of the matrix, accompanied by the pull-out of a small number of piercing fibers. Finally, the influences of the temperature, nut radius, and fixture geometry on the critical load were determined via simulation.

scholarly journals Scale and manufacturing effects on tensile strength of marine grade sandwich composite panel joints

2018 ◽  
Vol 22 (6) ◽  
pp. 1983-2008 ◽  
Author(s):  
Scott M Tomlinson ◽  
Roberto A Lopez-Anido
Keyword(s):  
Tensile Strength ◽  
Failure Mode ◽  
Shear Failure ◽  
Scale Effects ◽  
Composite Panel ◽  
Sandwich Composite ◽  
Full Size ◽  
Joint Design ◽  
Composite Joint ◽  
Nominal Strength

In this article, scale and manufacturing effects on the tensile strength of marine grade sandwich composite panels and joints are investigated to aid in the fabrication of large modular ship hulls. This is done by researching transverse sandwich composite joint design, experimental tension methods, and scale and manufacturing effects on tensile strength. Three scales are utilized in this investigation of tension characteristics: coupon scale, table-top single panel fabrication scale, and in position mock-up full-size fabrication scale. First, material properties are gathered through industry standard coupon scale fabrication and testing. Next, a single-infusion baseline panel along with two ship hull transverse joint designs are chosen, fabricated, tested, and compared at single panel scale. These tests include individually fabricated hull panels, as well as secondary structural stiffener sandwich composite web panels, and stiffener flange components. The highest performing joint design is then utilized in a mock-up full-size fabrication scale structure. This structure includes both a transverse hull joint, as well as joints in the secondary structural stiffener web and flange. This mock-up fabrication scale component was then cut apart and tested in tension. The novel sandwich composite panel joint tension experimentation methods used indicate the methods studied are reliable for determination of characteristic tensile properties, and that the joints selected are effective. Investigations concerning scale effects comparing baseline fiber failure mode tension results from the coupon scale to the single panel scale, and manufacturing effects comparing joint interlaminar shear failure mode from the single panel scale to the mock-up fabrication scale, show decreased ultimate tensile strength with increased overall part size and manufacturing complexity. These factors, applied to a reference strength to achieve a nominal strength, were found to range from 0.796 to 0.846.

Test Scheme and Result Analysis of New-Type Frame Structure with Column End of Steel-Concrete Composite Joint

2014 ◽  
Vol 919-921 ◽  
pp. 247-253
Author(s):  
Guan Hong Lu ◽  
Zhan Wang
Keyword(s):  
Load Test ◽  
Frame Structure ◽  
Test Scheme ◽  
Failure Characteristics ◽  
Comparative Tests ◽  
Short Columns ◽  
Composite Joint ◽  
New Type ◽  
Program Test ◽  
Result Analysis

The frame column and frame structure with column end of steel-concrete composite joint is a new-type architectural structure. To obtain the mechanical property of the new-type frame column and frame structure, comparative tests between 6 new-type columns and 3 ordinary columns and comparative tests between new-type frames and ordinary frames are carried out. This paper elabrately introduces the specimen design, experiment load, test program, test results and others. Thus, the transformation and failure characteristics of new-type long and short columns at different axial compression ratios and the transformation and failure characteristics of new-type grames at different prestresses are obtained. They are respectively compared with the ordinary long and short columns and frames. Results show that the seismic performance of the new-type column and frame structure is obviously superior to that of the ordinary ones. The tests can achieve the expected test objectives and are proved successful.

scholarly journals Experimental Study of the Mechanical Behavior of the Steel–Concrete Joints in a Composite Truss Bridge

2019 ◽  
Vol 9 (5) ◽  
pp. 854 ◽  
Author(s):  
Yingliang Tan ◽  
Bing Zhu ◽  
Tingyi Yan ◽  
Biao Huang ◽  
Xuewei Wang ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Bearing Capacity ◽  
Joint Stiffness ◽  
Composite Joints ◽  
Truss Bridges ◽  
Shear Connectors ◽  
Pull Out ◽  
Composite Joint ◽  
Concrete Joints ◽  
Truss Bridge

The mechanical behavior of the steel–concrete joints in a composite bridge was investigated. Pull-out tests on eight specimens were carried out to evaluate the connection performance of Perfobond rib shear connectors (PBL shear connectors). In addition, static load tests were conducted on three composite joint specimens with a scale of 1/2 in a composite truss bridge. The crack load, load–displacement curves, strain distribution, and the joint stiffness were obtained from the composite joint to analyze the mechanical behavior of steel–concrete joints. The experimental results show that the embedded depth plays an important role in the ultimate bearing capacity and the deformation of PBL shear connectors and could even change the failure mode. Based on the test results of composite joints, the displacement increased almost linearly with the horizontal load on the concrete chord. There was no evident failure, and large deformation occurred in composite joints. In addition, the ultimate loads obtained from three composite joint specimens were greater than 2.93 times the design load (2050 kN). These investigated composite joints had excellent bearing capacity (above 6000 kN). This study will provide an experimental reference for the design of steel–concrete joints for composite truss bridges.

scholarly journals Experimental Investigation of Fastener Pull-out Response in Composite Joints under Static and Dynamic Loading Rates

2019 ◽  
Vol 26 (5-6) ◽  
pp. 1349-1365
Author(s):  
Nikolaos Perogamvros ◽  
George Lampeas ◽  
Adrian Murphy
Keyword(s):  
Dynamic Loading ◽  
Damage Zone ◽  
Material System ◽  
Dynamic Tests ◽  
Loading Rates ◽  
Failure Patterns ◽  
Pull Out ◽  
Composite Joint ◽  
Static And Dynamic Tests ◽  
The Impact

Abstract A novel device is adopted in order to experimentally investigate the effect of various loading rates on the pull-out response of a fastened composite joint configuration. The joint coupons comprise a composite plate made of the carbon/epoxy AS4/8552 material system and a centrally located titanium lockbolt. Tensile-type (pull) loading was applied to the specimens in a velocity range from quasi-static to 2.1 m/s. Both quasi-static and dynamic tests were conducted using the same specimen geometry and boundary conditions, which conform to international and industrial standards. The experimental work expands the limited literature and understanding of the mechanical response of composite pull-out joints under the action of dynamic loading. The main experimental observations revealed an increase of 15% regarding maximum load values when loading rate shifts from the static to the impact regime, while the failure patterns derived from static and dynamic tests were similar, although the latter presented a more intense damage zone.

The influence of heat treatment on the fiber/matrix interface in a SiC-reinforced glassceramic

1988 ◽  
Vol 46 ◽  
pp. 742-743
Author(s):  
E. Bischoff ◽  
O. Sbaizero
Keyword(s):  
Heat Treatment ◽  
Aluminum Silicate ◽  
Lithium Aluminum ◽  
Interfacial Region ◽  
Specimen Preparation ◽  
Crack Wake ◽  
Pull Out ◽  
Annealed Material ◽  
Ultrasonic Drilling ◽  
Fiber Matrix Interface

Fiber or whisker reinforced ceramics show improved toughness and strength. Bridging by intact fibers in the crack wake and fiber pull-out after failure contribute to the additional toughness. These processes are strongly influenced by the sliding and debonding resistance of the interfacial region. The present study examines the interface in a laminated 0/90 composite consisting of SiC (Nicalon) fibers in a lithium-aluminum-silicate (LAS) glass-ceramic matrix. The material shows systematic changes in sliding resistance upon heat treatment.As-processed samples were annealed in air at 800 °C for 2, 4, 8, 16 and 100 h, and for comparison, in helium at 800 °C for 4 h. TEM specimen preparation of as processed and annealed material was performed with special care by cutting along directions having the fibers normal and parallel to the section plane, ultrasonic drilling, dimpling to 100 pm and final ionthinning. The specimen were lightly coated with Carbon and examined in an analytical TEM operated at 200 kV.

Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

1989 ◽  
Vol 47 ◽  
pp. 556-557
Author(s):  
K.L. More ◽  
R.A. Lowden
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Frictional Stress ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Carbon Coated ◽  
Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

Advances in ultramicrotomy for physical sciences applications

1993 ◽  
Vol 51 ◽  
pp. 710-711
Author(s):  
G. McMahon ◽  
T. Malis
Keyword(s):  
Particle Surface ◽  
Zeolite Catalysts ◽  
Physical Sciences ◽  
Pull Out ◽  
Large Particles ◽  
Novel Applications ◽  
Metal Wires ◽  
Frequent Problem ◽  
Specific Orientation ◽  
Diamond Knife

As with all techniques which are relatively new and therefore underutilized, diamond knife sectioning in the physical sciences continues to see both developments of the technique and novel applications.Technique Developments Development of specific orientation/embedding procedures for small pieces of awkward shape is exemplified by the work of Bradley et al on large, rather fragile particles of nuclear waste glass. At the same time, the frequent problem of pullout with large particles can be reduced by roughening of the particle surface, and a proven methodology using a commercial coupling agent developed for glasses has been utilized with good results on large zeolite catalysts. The same principle (using acid etches) should work for ceramic fibres or metal wires which may only partially pull out but result in unacceptably thick sections. Researchers from the life sciences continue to develop aspects of embedding media which may be applicable to certain cases in the physical sciences.

Pull-out behaviour of hooked steel fibres

10.1617/13472 ◽  
2005 ◽  
Vol 35 (251) ◽  
Author(s):  
P. Robins
Keyword(s):  
Steel Fibres ◽  
Pull Out
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