Strength Predication for Load-Bearing Lugs of Three-Dimensional Braided Composites

2007 ◽  
Vol 353-358 ◽  
pp. 1948-1951 ◽  
Author(s):  
Xi Tao Zheng ◽  
Qin Sun ◽  
Ying Nan Guo ◽  
Ya Nan Chai
Keyword(s):  
Failure Modes ◽  
Three Dimensional ◽  
Strain Gages ◽  
Braided Composites ◽  
Stress Concentrations ◽  
Shell Elements ◽  
Braided Composite ◽  
Load Response ◽  
Fiber Tension ◽  
Bearing Failures

Load response and failure modes of three-dimensional (3-d) four-directional braided composite lugs were studied analytically and experimentally. The objective of the study was to get information on the stiffness, strength and failure mode of the lug, as well as on the applicability of the analysis method used to predict lug load response and failure. The test lugs were manufactured with the RTM (Resin Transfer Molding) technique. The test specimens were loaded parallel to the lug centerline. Two types of specimens were tested to failure. Three of them were instrumented with 18 strain gages in each type of lug. There are three basic failure modes in braided composite joints: net-tension, shear-out, and bearing. Net-tension failure is associated with matrix and fiber tension failure due to stress concentrations. Shear-out and bearing failures result primarily from the shear and compression failures of fiber and matrix. The analyses were performed using finite element method. Shell elements were used. A steel pin was modeled to apply the loading. The loading was applied with a constant force distribution through the center of the pin. A contact was defined between the pin and the surrounding lug surface. The measured strains showed fairly good correlation with the analysis results. The strain response was almost linear. It can be concluded that with correct material properties the FE approach used in the analyses can provide a reasonable estimate for the load response and failure of 3-d braided composite lugs

Finite element analyses on punch shear behaviors of three-dimensional braided composites at microstructure level

2016 ◽  
Vol 26 (7) ◽  
pp. 968-988 ◽  
Author(s):  
Yuanyuan Li ◽  
Wei Zhang ◽  
Rotich K Gideon ◽  
Bohong Gu ◽  
Baozhong Sun
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
High Strain ◽  
Three Dimensional ◽  
Rate Sensitivity ◽  
Element Model ◽  
Shear Loading ◽  
Composite Panel ◽  
Braided Composites ◽  
Braided Composite

The punch shear properties of three-dimensional carbon/epoxy braided composites were studied at quasi-static and high strain rates with finite element method at microstructure level. A microstructure model was developed to analyze the stress distribution and progressive damage of the braided composite panel with different thickness. The braiding yarns were considered as an elastic and transversely isotropic material. Ductile and shear criterion were used in finite element model to obtain the damage evolution. It was found that the braided composite exhibited high strain rate sensitivity under punch shear loading. The thickness influences the punch shear strength significantly. The braiding yarns at surface and corner parts have tensile and pullout failure modes, while at inner part have shear damage mode.

Failure analysis of three-dimensional braided composite tubes under torsional load: Experimental study

2017 ◽  
Vol 36 (12) ◽  
pp. 878-888 ◽  
Author(s):  
Xiaopei Wang ◽  
Deng’an Cai ◽  
Chao Li ◽  
Fangzhou Lu ◽  
Yu Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Failure Modes ◽  
Shear Failure ◽  
Three Dimensional ◽  
Damage Mechanism ◽  
Test Device ◽  
Composite Tubes ◽  
Torsional Strength ◽  
Braided Composite ◽  
Torsional Load

An experimental study on the effects of braided processes on the torsional strength, torsional modulus and failure modes of the three-dimensional braided composite tubes are presented. Based on the movement of carries, the yarn traces of three-dimensional braided composite tubes are analyzed systematically. Four different three-dimensional braided composite tubes are formed by resin transfer molding, and a number of torsional tests are performed respectively using a special test device. It is found that the torsional strength of three-dimensional five-directional braided composite tubes is higher than others, while the torsional modulus of three-dimensional multi-layer wrapping braided composite tubes is the highest. Furthermore, the damage behaviors of 3D braided composite tubes are significantly influenced by braiding process. One focus is to evaluate the damage mechanism of three-dimensional braided composite tubes by cutting the specimens and using scanning electron microscopy. Under torsional load, three-dimensional five-directional braided composite tubes and three-dimensional surface-core five-directional braided composite tubes are fractured in compression and shear failure, while three-dimensional multi-layer wrapping braided composite tubes and three-dimensional seven-directional braided composite tubes are split open in tensile and shear failure.

Research on Fabricating Technology of Three Dimensional Integrated Braided Composite I Beam

2010 ◽  
Vol 136 ◽  
pp. 59-63 ◽  
Author(s):  
X.Y. Pei ◽  
Jia Lu Li
Keyword(s):  
Cross Section ◽  
High Performance ◽  
Research Result ◽  
Three Dimensional ◽  
Void Content ◽  
Braided Composites ◽  
Braided Composite ◽  
Transfer Molding ◽  
3D Braided Composites

In this paper the fabricating technology of three dimensional (3D) integrated braided composite I beam is researched, including: braiding technology of 3D braided I beam preform, the orientation of fiber-tow in the I beam preform, the optimizing of process parameters of resin transfer molding (RTM) for 3D braided composite I beam, and the design of mould for consolidation of composite I beam. The quality of 3D braided composites is good analyzed by ultrasonic A-scan, void content calculation and microscope observation. The research result will provide a good way for designing and fabricating high performance 3D integrated braided composite components with irregular cross section.

scholarly journals Short Beam Shear Behavior and Failure Characterization of Hybrid 3D Braided Composites Structure with X-ray Micro-Computed Tomography

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1931
Author(s):  
Liwei Wu ◽  
Xiaojun Sun ◽  
Chunjie Xiang ◽  
Wei Wang ◽  
Fa Zhang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Transverse Shear ◽  
Failure Modes ◽  
Hybrid Composites ◽  
Shear Loading ◽  
Micro Computed Tomography ◽  
Braided Composites ◽  
Braided Composite ◽  
Shear Property ◽  
Beam Shear

Three-dimensional braided composite has a unique spatial network structure that exhibits the characteristics of high delamination resistance, damage tolerance, and shear strength. Considering the characteristics of braided structures, two types of high-performance materials, namely, aramid and carbon fibers, were used as reinforcements to prepare braided composites with different hybrid structures. In this study, the longitudinal and transverse shear properties of 3D braided hybrid composites were tested to investigate the influences of hybrid and structural effects. The damage characteristics of 3D braided hybrid composites under short beam shear loading underwent comprehensive morphological analysis via optical microscopy, water-logging ultrasonic scanning, and X-ray micro-computed tomography methods. It is shown that the shear toughness of hybrid braided composite has been improved at certain degrees compared with the pure carbon fiber composite under both transverse and longitudinal directions. The hybrid braided composites with aramid fiber as axial yarn and carbon fiber as braiding yarn exhibited the best shear toughness under transverse shear loading. Meanwhile, the composites with carbon fiber as axial yarn and aramid fiber as braiding yarn demonstrated the best shear toughness in the longitudinal direction. Due to the different distribution of axial and braiding yarns, the transverse shear property of hybrid braided structure excels over the longitudinal shear property. The failure modes of the hybrid braided composite under the two loading directions are considerably different. Under transverse loading, the primary failure mode of the composites is yarn fracture. Under longitudinal loading, the primary failure modes are resin fracture and fiber slip. The extensive interfacial effects and the good deformation capability of the hybrid braided composites can effectively prevent the longitudinal development of internal cracks in the pattern, improving the shear properties of braided composites.

Enhancement of mechanical and electromagnetic absorbing properties of carbon/glass hybrid composites with a three-dimensional quasi-isotropic braided structure

2019 ◽  
Vol 89 (23-24) ◽  
pp. 4896-4905 ◽  
Author(s):  
Wei Fan ◽  
Lili Xue ◽  
Tongxue Wei ◽  
Jingjing Dong ◽  
Juanzi Li ◽  
...  
Keyword(s):  
Hybrid Composites ◽  
Glass Fibers ◽  
Three Dimensional ◽  
Laminated Composite ◽  
External Stress ◽  
Braided Composites ◽  
Braided Composite ◽  
Braided Structure ◽  
Electromagnetic Transmission ◽  
Ku Band

Two carbon/glass hybrid composites with different reinforced structures were designed and their mechanical and electromagnetic absorbing properties (EMAPs) were investigated in this paper. It was found that the tensile, bending, and double-notch shear strength of the three-dimensional (3D) quasi-isotropic (QI)-braided composite were 4.50%, 9.64%, and 14.29% higher than those of the QI-laminated composite, respectively. This was because Z-binder yarns in the 3D QI-braided composite can lock all yarn sets together to bear external stress and inhibit crack propagation in interlamination. The EMAPs of the 3D QI-braided composites were larger than that of the QI-laminated composite in the entire Ku band. This was because the Z-directional glass fibers in the 3D QI-braided composite were beneficial for electromagnetic transmission. The uniform arrangement of five sets of yarns (+45°, –45°, 90°, 0°, and Z-yarns) resulted in the 3D QI-braided composites having better QI-EMAPs and QI mechanical properties in plane and outstanding interlayer performance than the traditional carbon fiber laminated composite.

Three-dimensional braided composites with zero, negative and isotropic thermal expansion behavior

2020 ◽  
Vol 54 (13) ◽  
pp. 1761-1781
Author(s):  
SA Pottigar ◽  
B Santhosh ◽  
RG Nair ◽  
P Punith ◽  
PJ Guruprasad ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Three Dimensional ◽  
Braided Composites ◽  
Fiber Volume ◽  
Braided Composite ◽  
Expansion Behavior ◽  
Unit Cells ◽  
Composite Configuration

Three-dimensional braided composites with zero, negative and isotropic coefficient of thermal expansion are presented based on an analytical homogenization technique. The configuration of the braided composites is worked out considering the exact jamming condition leading to higher fiber volume fraction. A total of four configurations of three-dimensional-braided composite representative unit cells were analyzed. Among these, two arrangements are 4-axes and the other two are 5-axes. Special emphasis is given on the detailed description of the representative unit cells. Analysis reveals that a three-dimensional-braided composite configuration with thermoelastic isotropic properties having same coefficient of thermal expansion along x-, y-, and z-axes is achievable. As a special case, the homogenization model is used to predict, for the first time, a configuration of braided architecture and material leading to zero coefficient of thermal expansion along x-, y- and z-directions.

Research on Health Monitor for Three-Dimensional Braided Composite Material

2011 ◽  
Vol 48-49 ◽  
pp. 1389-1394
Author(s):  
Yi Li ◽  
Zhen Kai Wan ◽  
Jia Lu Li
Keyword(s):  
Composite Materials ◽  
Health Monitoring ◽  
Three Dimensional ◽  
Dynamic Monitoring ◽  
Monitoring Methods ◽  
Braided Composites ◽  
Monitoring Method ◽  
Braided Composite ◽  
3D Braided Composites ◽  
Health Monitor

This paper describes two methods of Fiber Bragg Grating (FBG) embedded in the three-dimensional (3D) braded composite materials and acoustic emission health monitor for 3D braided composite materials condition. The paper mainly analyses the relations of FBG change and the inner straining under the stretching on materials. It is provided that the way of signal collection and processing. The experimental results proved that FBG sensors have exceptional sense characteristic. The braided angle of composites has a little influence on FBG signal. FBG embedded in the 3D braided composite materials has not more effect mechanical property of materials. According to two health monitoring methods and the particularity of 3D braided composites, the health monitoring method based on FBG much more applies to dynamic monitoring on 3D composites special field. This research provides basis for the study and application of advanced intelligent composites.

An Engineering Assessment Methodology to Evaluate Arc Burns

2020 ◽  
Author(s):  
Alireza Kohandehghan ◽  
Jonathan Prescott ◽  
Stuart Guest ◽  
Sean Lepine
Keyword(s):  
Failure Modes ◽  
Load Capacity ◽  
Three Dimensional ◽  
Complete Removal ◽  
Assessment Method ◽  
Accelerated Cooling ◽  
Metal Loss ◽  
Assessment Methodology ◽  
Stress Concentrations ◽  
Girth Welds

Abstract Arc burns, also known as arc strikes, are caused by momentary interaction of an electric arc, e.g., welding electrode or welding ground clamp, and a pipe or fitting, upon which a minimal or no amount of weld metal is deposited. Arc burns typically correspond with localized alteration of microstructures, shallow pitting, sharp surface contours, re-melting, and/or cracking. The damaged microstructures manifest in the form of a locally harder material due to accelerated cooling rates. Arc burns mainly form during the pipeline construction and are typically located adjacent to manually installed girth welds. The hard microstructures associated with arc burns are susceptible to hydrogen-induced cracking (HIC) in the presence of atomic hydrogen. Pipeline maintenance codes consider arc burns as defects and require their complete removal by grinding. Due to the relatively small dimension of arc burns, removal by grinding followed by etching contrast test is often the simplest and most reliable permanent repair for such defects. However, in some circumstances grinding to the maximum allowable depth may not completely remove the affected microstructures. Also, removal of arc burns often requires grinding near girth welds and significant grinding depths may require through-thickness inspection of the welds to ensure safety. Type B pressure containing steel sleeves are another permanent repair method that can be used to repair arc burns or partially removed arc burns within grinding metal loss features. Installation of permanent repairs over an arc burn is costly and may introduce additional or higher risks to the integrity of pipeline when scarce industry studies are available that conclusively demonstrate the dangers of leaving arc burns or partially removed arc burns in pipes. Despite the need, there is no validated engineering assessment method for the evaluation of arc burns. This paper will summarize an engineering assessment methodology and the findings of the evaluation of crack-free arc burns and partially removed arc burn features for two scenarios on vintage liquid pipelines. A combination of one- and three-dimensional finite element models was utilized to investigate the effect of arc burns and/or partially removed arc burns on the integrity of the pipeline based on plastic collapse, local yielding, and fatigue failure modes. The effect of the buried pipeline profile and soil was considered in the assessment of the axial load capacity of the pipeline. The geometrical and metallurgical stress concentrations of the features were considered in the engineering assessment. The engineering assessment determined if the pipeline with the arc burns and/or partially removed arc burns can survive rupture, brittle fracture, and fatigue damage mechanisms during its operation and if reinforcement of the area or cut-out is required.

Research on FBG in 3-D Braided Composite Structure Health Monitoring

2011 ◽  
Vol 298 ◽  
pp. 68-72 ◽  
Author(s):  
Ming Wei Ding ◽  
Zhen Kai Wan ◽  
Yong Xin Ma
Keyword(s):  
Health Monitoring ◽  
Composite Structure ◽  
Three Dimensional ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Braided Composites ◽  
Structure Health Monitoring ◽  
Braided Composite ◽  
Fundamental Structure ◽  
Monitoring Temperature

In this work, the application status and significance of Fiber Bragg Gratings（FBGs） and Three-dimensional (3-D) braided composites were briefly introduced, so were the fundamental structure of 3-D braided composites and the sensing mechanism of FBGs in them. Combined with the characteristics of 3-D braiding technology, this paper presents a primary theoretical solution for synchronously monitoring temperature and strain inside Three-dimensional (3-D) braided composites, and further analysis were made about it. It was shown by experiment that the application of FBGs in the structure health monitoring in 3-D braided composites has great potential.

Characteristic analysis of carbon nanotube thread embedded into three-dimensional braided composite under bending load

2017 ◽  
Vol 24 (5) ◽  
pp. 791-798 ◽  
Author(s):  
Jian-Min Guo ◽  
Li-Ying Gong ◽  
Yan Liu
Keyword(s):  
Carbon Nanotube ◽  
Compressive Loading ◽  
Three Dimensional ◽  
Strain Sensing ◽  
Braided Composites ◽  
Characteristic Analysis ◽  
Resistance Change ◽  
Braided Composite ◽  
Bending Load ◽  
Embedded Method

AbstractIn this paper, we introduce an embedded method of carbon nanotube threads (CNTs) in three-dimensional (3-D) braided composite material preform. We investigate the strain sensing properties of CNTs embedded into 3-D braided composites using three-point bend test under different loads. The resistance change rate properties of CNTs in composites under tensile and compressive loading are analyzed in detail. Experimental results show that in the three-point bending process, the resistance of CNTs exponentially increases with the increase of strain until the specimen loading to fracture. Moreover, the residual resistance of CNTs has been observed after unloading. Our experiments have shown that structure health status of 3-D braided composites can be sensed and monitored in real-time using CNTs sensor under bending load. This study provides an experimental basis to lay the foundation for the structural health monitoring system construction of 3-D braided composites.

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