scholarly journals That which fits the mold: a braided composite wing

2019 ◽  
Vol 2 (2) ◽  
pp. 63-64
Author(s):  
Nabiha Saghar ◽  
Eric Lepp ◽  
Ahmed Ead ◽  
Jason Carey

In this design study, a model airplane wing, partially constructed from braided composite panels, was made for the purpose of demonstrating the applications of braided composites for aerospace components. Fibres of Kevlar® were braided together along a tubular surface, then subsequently cut and unrolled to form two planar sheets of interlaced yarns that could be laid down in a 3D printed mold to later be coated in resin. The mold consisted of four parts: two female parts to shape the composite wing panels and two male parts to compress the composite. When connected together they form a fused core. A fibre sheet was draped over each female part, and its extraneous edges were folded inward to form a second layer as reinforcement. Each sheet was then laid up with Ecopoxy® resin and allowed to cure while sandwiched between the female mold and its corresponding male component. Upon disassembly of the mold system, a braided composite wing panel had formed upon both halves of the 3D printed core. The external portion of each panel was found to be smooth with few irregularities that could potentially compromise their aerodynamic performance. The mold was constructed to facilitate the process of cold-curing rather than curing at an elevated temperature. For heated cure process, the use of metal would be recommended because it generally deforms negligibly through heating and cooling. A metal mold would also be used to ease the process of debonding from the composite materials. Care should be taken to ensure that fibre orientation is consistent. The results illustrate how a mold can be fabricated to facilitate the process of curing braided composites, and can serve to improve the quality of products that require a higher strength to weight ratio.  

2019 ◽  
Vol 2 (2) ◽  
pp. 57-58
Author(s):  
Mackenzie Neufeld ◽  
Ahmed Samir Ead ◽  
Eric Lepp

Current badminton rackets are typically made out of steel, aluminium, or carbon fibre. Although these materials perform acceptably, there are some downsides to their properties. However, these non-ideal characteristics of badminton rackets may be overcome with the usage of different manufacturing materials, specifically braided composites. An example of a braided material is KevlarⓇ. Kevlar is a heat resistant and high strength synthetic fibre that can be manufactured into braids using a maypole braiding system. These Kevlar braids can then be manipulated to a preferred shape for the curing process. In order to come up with a feasible design to base the prototype, a 3D modelling software (SolidWorksTM) is used. This ensures geometrical viability and possible to manufacture of the prototype. Modeling a badminton racket on Solidworks required the modelling of a racket head, and handle. The head was created using 2 ellipses, one of which acted as a skeleton, or mould for the Kevlar braid, and the other was a hollow ellipse which encompassed the mold and acted as the Kevlar braid. The solid ellipse was created in two halves, each having either an extrusion or a hole in the ends. This allowed them to easily attach to form a full ellipse. Once modeled, the solid ellipse was 3D printed to act as the curing mandrel, an internal skeleton for the Kevlar braids. In order to attach the head to the handle, a three-part connector piece was created and 3D printed. The rod of the racket was not created with an internal skeleton because the flexibility would falter. Instead, the Kevlar braids were slid off the material after curing and attached to the racket heads connector piece. In order to have a balanced weight ratio throughout the racket, the grip was created with an internal 3D printed skeleton. This structure allowed for a feasible, flexible, and strong Kevlar based product.


2021 ◽  
Vol 11 (8) ◽  
pp. 3466
Author(s):  
Lulu Liu ◽  
Shikai Yin ◽  
Gang Luo ◽  
Zhenhua Zhao ◽  
Wei Chen

Two-dimensional (2D) triaxial braided composites with braiding angle (± 60°/0°) have been used as aero-engine containing casing material. In the current paper, three types of projectile with the same mass and equivalent diameter, including cylinder gelatin projectile, carbon fiber-reinforced plastics (CFRP), and titanium alloy blade-like projectile, were employed to impact on triaxial braided composites panels with thickness of 4.3 mm at room temperature (20 °C) to figure out the influences of projectile materials on the damage pattern and energy absorption behavior. Furthermore, the influences of environmental temperature were also discussed considering the aviation service condition by conducting ballistic impact tests using CFRP projectile at cryogenic temperature (−50 °C) and high temperature (150 °C). The triaxial braided target panel were pre-heated or cooled in a low-temperature chamber before mounted. It is found that soft gelatin project mainly causes global deformation of the target and therefore absorb much more energy. The triaxial braided composite absorb 77.59% more energy when impacted with CFRP projectile than that with titanium alloy projectile, which mainly results in shear fracture. The environmental temperature has influences on the damage pattern and energy absorption of triaxial braided composites. The cryogenic temperature deteriorates the impact resistance of the triaxial braided composite material with matrix cracking damage pattern, while high temperature condition improves its impact resistance with shearing fracture damage pattern.


Author(s):  
Mohammadreza Lalegani Dezaki ◽  
Mohd Khairol Anuar Mohd Ariffin ◽  
Diniesh Appalanaidoo ◽  
Zaliha Wahid ◽  
Abdullahi Musse Rage

2010 ◽  
Vol 136 ◽  
pp. 59-63 ◽  
Author(s):  
X.Y. Pei ◽  
Jia Lu Li

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.


2018 ◽  
Vol 15 ◽  
pp. 104-108
Author(s):  
Luboš Řehounek ◽  
Petra Hájková ◽  
Petr Vakrčka ◽  
Aleš Jíra

Construction applications sometimes require use of a material other than construction steel or concrete – mainly in cases, where strength to weight ratio needs to be considered. A suitable solution to this problem are structures manufactured using the 3D printing process, as they have a very good strength to weight ratio (i.e.: Ti-6Al-4V – σ<sub>ult</sub> = 900 MPa and ρ = 4500 kg/m<sup>3</sup>). Trabecular structures are porous structures with local material characteristics identical to their commonly manufactured counterparts, but due to their geometry, they have different global mechanical properties and are suited for special applications. We designed and manufactured six variants of these structures and subjected them to uniaxial compression tests, nanoindentation tests and subsequently evaluated their differences and elastic moduli. The values of global moduli E are in the range of 2.55 GPa – 3.55 GPa for all specimens.


Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1931
Author(s):  
Liwei Wu ◽  
Xiaojun Sun ◽  
Chunjie Xiang ◽  
Wei Wang ◽  
Fa Zhang ◽  
...  

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.


2019 ◽  
Vol 89 (23-24) ◽  
pp. 4896-4905 ◽  
Author(s):  
Wei Fan ◽  
Lili Xue ◽  
Tongxue Wei ◽  
Jingjing Dong ◽  
Juanzi Li ◽  
...  

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.


2020 ◽  
Vol 54 (13) ◽  
pp. 1761-1781
Author(s):  
SA Pottigar ◽  
B Santhosh ◽  
RG Nair ◽  
P Punith ◽  
PJ Guruprasad ◽  
...  

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.


1950 ◽  
Vol 162 (1) ◽  
pp. 199-204 ◽  
Author(s):  
J. J. Granville

The development of high-pressure processes (200–1,500 atm.) in the chemical industry in recent years, often carried out at high temperatures, has helped considerably to cheapen the production of basic materials, such as ammonia and methanol, and has opened up entirely new fields, particularly in the manufacture of important plastic materials, in coal hydrogenation, and in oil-cracking operations, calling for special equipment and novel techniques. This paper deals with the mechanical requirements for high-pressure vessels, and traces progressive changes in their construction during the last thirty years, from cast autoclaves to forged vessels and to modern composite designs, having due regard to the volume-to-weight ratio, construction, inspection, cost, and maintenance. Stress distributions in the cylinder wall, suitable closure mechanisms, the effects of temperature, chemical and physical attacks, and the provisions for stirring, heating, and cooling are discussed. A brief account of the control mechanisms involved and of the necessary vital safety precautions is given.


2007 ◽  
Vol 353-358 ◽  
pp. 1948-1951 ◽  
Author(s):  
Xi Tao Zheng ◽  
Qin Sun ◽  
Ying Nan Guo ◽  
Ya Nan Chai

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


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