Mechanical Properties of Aramid Composite as an Alternative in Use of Steel on the Manufacture of CN-235 Aircraft Wings

The use of steel in aerospace manufacture continues to decrease, owing in part to the sustainability and mechanical properties of fibers which have higher strength in minimum weight than steel. This study was defined to evaluate the mechanical properties of high-performance fibers, especially aramid, in terms of composite to be part of aircraft' wings called CN-235. The reinforcements were pre-impregnated by the materials manufacturers, under heat and pressure, with a pre-catalysed resin. Then the layering of aramid prepregs was carried with a dry lay-up process and cured in the autoclave at a temperature of 125°C and pressure of 3 bar for 90 minutes. The aramid composite was cured in various grain directions and examined in mechanical tests such as tensile, compression, and interlaminar shear strength tests. The result showed an insignificant difference between 0 and 90 degrees of grain direction in aramid composite in any properties. The strength of aramid composite with 90 degrees of grain direction has a higher value in the compression test (less than 5%) while having lower value in tensile and interlaminar shear tests.

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Mechanical properties of multiwall carbon nanotubes/unidirectional carbon fiber-reinforced epoxy hybrid nanocomposites in transverse and longitudinal fiber directions

Polymers and Polymer Composites ◽

10.1177/0967391120986516 ◽

2021 ◽

pp. 096739112098651

Author(s):

Saeedeh Saadatyar ◽

Mohammad Hosain Beheshty ◽

Razi Sahraeian

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

Epoxy Resin ◽

Interlaminar Shear Strength ◽

Lap Shear Strength ◽

Transverse Tensile ◽

Lap Shear ◽

Longitudinal Fiber ◽

Interlaminar Shear ◽

Multiwall Carbon

Unidirectional carbon fiber-reinforced epoxy (UCFRE) is suffering from weak transverse mechanical properties and through-thickness properties. The effect of different amount (0.1, 0.3 and 0.5 phr which is proportional to 0.09, 0.27 and 0.46 wt%, respectively) of multiwall carbon nanotube (MWCNT), on transverse tensile properties, flexural strength, fracture toughness in transverse and longitudinal fiber directions, interlaminar shear strength and lap shear strength of UCFRE has been investigated. Dicyandiamide was used as a thermal curing agent of epoxy resin. MWCNT was dispersed in the epoxy resin by ultrasonic instrument and their dispersion state was investigated by scanning electron microscopy (SEM). The curing behavior of epoxy resin and its nanocomposites was assessed by differential scanning calorimetry. Results show that transverse tensile strength, modulus and strain-at-break were increased by 28.5%, 25% and 14%, respectively by adding 0.1 phr of MWCNT. Longitudinal flexural properties of UCFRE was not changed by adding different amount of MWCNT. Although longitudinal flexural strength was increased by 5% by adding 0.1 phr of MWCNT. Fracture toughness in transverse and longitudinal fiber directions was increased by 39% and 9%, respectively at 0.3 phr of MWCNT. Results also show that interlaminar shear strength and lap shear strength were increased at 0.3 phr of MWCNT by 8% and 5%, respectively. These increases in mechanical properties were due to the good adhesion of fibers to the matrix, interlocking and toughening action of MWCNT as revealed by SEM.

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Fast Preparation of High-Performance Wood Materials Assisted by Ultrasonic and Vacuum Impregnation

Forests ◽

10.3390/f12050567 ◽

2021 ◽

Vol 12 (5) ◽

pp. 567

Author(s):

Hong Yang ◽

Mingyu Gao ◽

Jinxin Wang ◽

Hongbo Mu ◽

Dawei Qi

Keyword(s):

Mechanical Properties ◽

High Performance ◽

Mechanical Tests ◽

Vacuum Impregnation ◽

Natural Forests ◽

Ultrasonic Pretreatment ◽

Fast Growing ◽

Before And After ◽

New Material ◽

Ft Ir

In the absence of high-quality hardwood timber resources, we have gradually turned our attention from natural forests to planted fast-growing forests. However, fast-growing tree timber in general has defects such as low wood density, loose texture, and poor mechanical properties. Therefore, improving the performance of wood through efficient and rapid technological processes and increasing the utilization of inferior wood is a good way to extend the use of wood. Densification of wood increases the strength of low-density wood and extends the range of applications for wood and wood-derived products. In this paper, the effects of ultrasonic and vacuum pretreatment on the properties of high-performance wood were explored by combining sonication, vacuum impregnation, chemical softening, and thermomechanical treatments to densify the wood; then, the changes in the chemical composition, microstructure, and mechanical properties of poplar wood before and after treatment were analyzed comparatively by FT-IR, XRD, SEM, and mechanical tests. The results showed that with ultrasonic pretreatment and vacuum impregnation, the compression ratio of high-performance wood reached its highest level and the MOR and MOE reached their maximums. With the help of this method, fast-growing softwoods can be easily prepared into dense wood materials, and it is hoped that this new material can be applied in the fields of construction, aviation, and automobile manufacturing.

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Surface Modification of Carbon Fibers by Grafting PEEK-NH2 for Improving Interfacial Adhesion with Polyetheretherketone

Materials ◽

10.3390/ma12050778 ◽

2019 ◽

Vol 12 (5) ◽

pp. 778 ◽

Cited By ~ 10

Author(s):

Elwathig. Hassan ◽

Tienah. Elagib ◽

Hafeezullah Memon ◽

Muhuo Yu ◽

Shu Zhu

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

Carbon Fibers ◽

Interfacial Adhesion ◽

Mechanical Analysis ◽

Interlaminar Shear Strength ◽

Thermoplastic Composites ◽

Negative Effects ◽

Covalent Bonds ◽

Interlaminar Shear

Due to the non-polar nature and low wettability of carbon fibers (CFs), the interfacial adhesion between CFs and the polyetheretherketone (PEEK) matrix is poor, and this has negative effects on the mechanical properties of CF/PEEK composites. In this work, we established a modification method to improve the interface between CFs and PEEK based chemical grafting of aminated polyetheretherketone (PEEK-NH2) on CFs to create an interfacial layer which has competency with the PEEK matrix. The changed chemical composition, surface morphology, surface energy, and interlaminar shear strength were investigated. After grafting, the interlaminar shear strength (ILSS) was improved by 33.4% due to the covalent bonds in the interface region, as well as having good compatibility between the interface modifier and PEEK. Finally, Dynamic Mechanical Analysis (DMA) and Scanning Electron Microscopy (SEM) observation also confirmed that the properties of the modified CF/PEEK composites interface were enhanced. This work is, therefore, a beneficial approach towards enhancing the mechanical properties of thermoplastic composites by controlling the interface between CFs and the PEEK matrix.

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Effect of Graphene Oxide on Interfacial Interactions and Fracture Toughness of Basalt Fiber-Reinforced Epoxy Composites

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.18803 ◽

2020 ◽

Vol 20 (11) ◽

pp. 6760-6767

Author(s):

Seong Hwang Kim ◽

Soo-Jin Park

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Graphene Oxide ◽

High Performance ◽

Basalt Fiber ◽

Superior Performance ◽

Microstructured Fibers ◽

Multi Scale ◽

Fundamental Understanding ◽

Interlaminar Shear

Multiscale hierarchy is a promising chemical approach that provides superior performance in syner-gistically integrated microstructured fibers and nanostructured materials in composite applications. The main purpose of this work was to introduce graphene oxide (GO) between an epoxy matrix and basalt fibers to improve mechanical properties by enhancing interfacial adhesion. The composites were reinforced with various concentrations of GO. For all of the fabricated composites, the optimum GO content was found to be 0.5 wt%, which improved the interlaminar shear strength and fracture toughness by 66.2% and 86.1%, respectively, compared with those of neat composites. We observed a direct linear relationship between fracture toughness and certain surface free energy. In addition, the fracture toughness mechanisms were illustrated using a crack theory based on morphology analyses of fracture surfaces. Such an effort could accelerate the conversion of multi-scale composites into high-performance materials and provide rational guidance and fundamental understanding toward realizing the theoretical limits of mechanical properties.

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Effect of Graphene Additive on Flexural and Interlaminar Shear Strength Properties of Carbon Fiber-Reinforced Polymer Composite

Journal of Composites Science ◽

10.3390/jcs4040162 ◽

2020 ◽

Vol 4 (4) ◽

pp. 162

Author(s):

Mohamed Ali Charfi ◽

Ronan Mathieu ◽

Jean-François Chatelain ◽

Claudiane Ouellet-Plamondon ◽

Gilbert Lebrun

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

Carbon Fiber ◽

Flexural Strength ◽

Interlaminar Shear Strength ◽

Fiber Reinforced Polymer ◽

Carbon Fiber Reinforced Polymer ◽

Adhesion Properties ◽

Reinforced Polymer ◽

Interlaminar Shear

Composite materials are widely used in various manufacturing fields from aeronautic and aerospace industries to the automotive industry. This is due to their outstanding mechanical properties with respect to their light weight. However, some studies showed that the major flaws of these materials are located at the fiber/matrix interface. Therefore, enhancing matrix adhesion properties could significantly improve the overall material characteristics. This study aims to analyze the effect of graphene particles on the adhesion properties of carbon fiber-reinforced polymer (CFRP) through interlaminar shear strength (ILSS) and flexural testing. Seven modified epoxy resins were prepared with different graphene contents. The CFRP laminates were next manufactured using a method that guarantees a repeatable and consistent fiber volume fraction with a low porosity level. Short beam shear and flexural tests were performed to compare the effect of graphene on the mechanical properties of the different laminates. It was found that 0.25 wt.% of graphene filler enhanced the flexural strength by 5%, whilst the higher concentrations (2 and 3 wt.%) decreased the flexural strength by about 7%. Regarding the ILSS, samples with low concentrations (0.25 and 0.5 wt.%) demonstrated a decent increase. Meanwhile, 3 wt.% slightly decreases the ILSS.

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Intralaminar Reinforcement for Biomimetic Toughening of Bismaleimide Composites Using Nanostructured Materials

Materials ◽

10.1115/imece2005-81689 ◽

2005 ◽

Author(s):

Thomas Tiano ◽

Margaret Roylance ◽

Benjamin Harrison ◽

Richard Czerw

Keyword(s):

Shear Strength ◽

Carbon Fiber ◽

Laminated Composite ◽

High Strength ◽

Interlaminar Shear Strength ◽

Aircraft Wings ◽

Trailing Edges ◽

Interlaminar Shear ◽

Strength And Stiffness ◽

Walled Carbon Nanotubes

Many conventional composite materials are composed of multiple layers of continuous fiber reinforced resin produced by lamination of b-staged prepreg and subsequent cure. These materials exhibit very high strength and stiffness in the plane, dominated by the properties of the fibers. The Achilles heel of such composites is the interlaminar strength, which is dependent on the strength of the unreinforced resin, often leading to failure by delamination under load. Current methods for increasing the interlaminar shear strength of composites consist of inserting translaminar reinforcement fibers through the entire thickness of a laminated composite, such as z-pin technology developed by Foster-Miller [1]. While effective, this technique adds several processing steps, including ultrasonic insertion of the z-pins into the laminate, subsequently causing a significant cost increase to laminated composites. Described in this paper is a process utilizing single-walled carbon nanotubes (SWNTs) and vapor grown carbon nanofibers as reinforcing elements promoting interlaminar shear strength and toughness in carbon fiber/bismaleimide (BMI) resin composites. The resulting composites mimic the natural reinforcing mechanism utilized in insect cuticles. Three different methods of increasing the affinity of these carbon nanofillers for the BMI matrix were explored. The mechanical properties of these composites were assessed using end notch flexure testing. The results indicated that including nanofiller at the laminae interface could increase the interlaminar shear strength of carbon fiber/BMI composites by up to 58%. SEM micrographs revealed that the nanofiller successfully bridged the laminae of the composite, thus biomimicking the insect cuticle. Composite fabrication techniques developed on this program would have a wide variety of applications in space and aerospace structures including leading and trailing edges of aircraft wings.

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Effect of storage time and chlorhexidine addition on the mechanical properties of glass ionomer cements

Brazilian Journal of Oral Sciences ◽

10.20396/bjos.v16i0.8650457 ◽

2017 ◽

Vol 16 ◽

pp. 1-9

Author(s):

Juliana de Carvalho Machado ◽

Cristiane Duque ◽

Josânia Pitzer de Oliveira ◽

Angela Scarparo Caldo-Teixeira

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Compressive Strength ◽

Storage Time ◽

Mechanical Characteristics ◽

Mechanical Tests ◽

Glass Ionomer Cements ◽

Glass Ionomer ◽

Strength Tests ◽

Storage Times

Aims: To evaluate the effect of the chlorhexidine (CHX) incorporation and the storage time on the mechanical properties of glass ionomer cements (GICs). Methods: The following GICs were evaluated: Ketac Molar Easymix (KM), Vidrion R (VR) and Vitromolar (VM), containing or not CHX. GIC liquid was modified by adding 1.25 % CHX digluconate and then manipulated with the power and placed into the stainless steel cylindrical or bar-shaped molds. GICs specimens were stored into water for 1, 7 and 28 days. After these periods, specimens were submitted to flexural, diametral tensile and compressive strength tests, according to ISO standards. Data from mechanical tests were statistically analyzed using 2-way ANOVA and Tukey tests. Results: Overall, the storage time did not influence any of the mechanical properties of the GICs tested. In contrast, the inclusion of CHX reduced significantly these properties for all GICs tested. KM presented the highest values of compressive strength for all storage times. KM + 1.25% CHX had lower compressive strength results than KM, however, it showed similar results when compared to another GICs without CHX. Conclusions: The presence of chlorhexidine, independent of the storage time, interfered on the mechanical characteristics of GIC.

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The mechanical performance of the laminated aluminum-epoxy/glass fiber composites containing halloysite nanotubes: An experimental investigation

Journal of Industrial Textiles ◽

10.1177/1528083720960735 ◽

2020 ◽

pp. 152808372096073

Author(s):

Marwa A Abd El-baky ◽

Mohamed A Attia

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

Tensile Strain ◽

Mechanical Performance ◽

Flexural Modulus ◽

Halloysite Nanotubes ◽

Interlaminar Shear Strength ◽

Plane Shear ◽

Bearing Strength ◽

Interlaminar Shear

In this study, the effect of different weight percentages (wt. %) of halloysite nanotubes (HNTs) on the mechanical performance of glass laminate aluminum (Al) reinforced epoxy (GLARE) was investigated. GLARE (3/2) laminates with quasi-isotropic lay-up, [Al/[(0°/90°)/(45°/−45°)]s/Al/[(0°/90°)/(45°/−45°)]s/Al] filled with 0, 0.25, 0.5, 1, 2 and 3 wt. % of HNTs were fabricated using hand lay-up followed by compression molding. To explore the effect of HNTs on the mechanical properties, tensile, flexural, in-plane shear, interlaminar shear, bearing and impact tests were conducted. Results demonstrated that the inclusion of 1 wt. % of HNTs into GLARE leads to maximum improvements of 35.67, 8.50, 28.85, 50.47, 50.27, 30.43, 23.73, 72.08, 30.74, and 51.52% in tensile strength, tensile strain, Young's modulus, modulus of toughness, flexural strength, flexural strain, in-plane shear strength, interlaminar shear strength, bearing strength, and impact strength, respectively, compared to pristine GLARE. An enhancement of 38.89% in the flexural modulus was attained by adding 0.5 wt. % of HNTs to GLARE compared to pristine GLARE. The tensile strength, tensile strain, modulus of toughness, flexural strength, flexural modulus, flexural strain, in-plane shear strength, and interlaminar shear strength of GLARE filled with 3 wt. % of HNTs are 0.91, 0.88, 0.91, 0.91, 0.71, 0.83, 0.85, and 0.91 times those of the original GLARE. But Young’s modulus, bearing strength, and impact strength are 1.10, 1.15 and 1.20 times those of the original GLARE. To investigate the fracture mechanism, field emission scanning electron microscope (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX) were used. The microscopic images revealed that adding HNTs lead to the improvement in the interaction between the epoxy matrix and glass fiber, thereby improving the mechanical properties.

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Polyimide fabric-reinforced polyimide matrix composites with excellent thermal, mechanical, and dielectric properties

High Performance Polymers ◽

10.1177/0954008320928387 ◽

2020 ◽

Vol 32 (10) ◽

pp. 1085-1093 ◽

Cited By ~ 1

Author(s):

Zonghu Pan ◽

Shuhao Han ◽

Jianhua Wang ◽

Shengli Qi ◽

Guofeng Tian ◽

...

Keyword(s):

Dielectric Constant ◽

Dielectric Properties ◽

High Performance ◽

Interlaminar Shear Strength ◽

Resin Composites ◽

Matrix Composites ◽

Air Atmosphere ◽

Interlaminar Shear ◽

Thermoforming Process ◽

Polyimide Matrix

Two types of thermosetting polyimide (PI) resin were prepared using a polymerization monomeric reactant method, and high performance PI fabric/PI resin composites were fabricated through a wet infiltration and thermoforming process. The properties of a PI fabric, PI resin, and PI/PI composites were comprehensively analyzed. The experimental results indicate that a resin end-capped with phenylacetylene achieves a better processability and heat resistance. The two composites exhibit excellent thermal, mechanical, and dielectric properties. They achieve a glass transition temperature of higher than 320°C and a 5% weight loss temperature of over 600°C under an air atmosphere. During mechanical testing, an interlaminar shear strength exceeding 35 MPa was achieved, whereas the maximum flexural strength was found to be greater than 400 MPa. Moreover, their dielectric constant at 1 MHz was below 3.4, with a dielectric loss of no more than 0.01.

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