scholarly journals Influence of the Epoxy Resin Process Parameters on the Mechanical Properties of Produced Bidirectional [±45°] Carbon/Epoxy Woven Composites

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1273
Author(s):  
Claudia A. Ramírez-Herrera ◽  
Isidro Cruz-Cruz ◽  
Isaac H. Jiménez-Cedeño ◽  
Oscar Martínez-Romero ◽  
Alex Elías-Zúñiga
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Composite Laminates ◽  
Tensile Tests ◽  
Woven Composites ◽  
Conversion Degree ◽  
Processing Conditions ◽  
Aerospace Applications ◽  
Resin Curing ◽  
Fiber Fabric

This work focuses on investigating the curing process of an epoxy-based resin—Aerotuf 275-34TM, designed for aerospace applications. To study the curing degree of Aerotuf 275-34TM under processing conditions, woven carbon fiber fabric (WCFF)/Aerotuf 275-34TM composite laminates were produced by compression molding using different processing temperatures (110, 135, 160, and 200 °C) during 15 and 30 min. Then, the mechanical behavior of the composite laminates was evaluated by tensile tests and correlated to the resin curing degree through Fourier-transform infrared spectroscopy (FTIR) analysis. The results show the occurrence of two independent reactions based on the consumption of epoxide groups and maleimide (MI) double bonds. In terms of epoxide groups, a conversion degree of 0.91 was obtained for the composite cured at 160 °C during 15 min, while the measured tensile properties of [±45°] WCFF/Aerotuf 275-34TM laminates confirmed that these epoxy resin curing processing conditions lead to an enhancement of the composite mechanical properties.

scholarly journals Microstructural Characterization and Mechanical Properties of L-PBF Processed 316 L at Cryogenic Temperature

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5856
Author(s):  
Pragya Mishra ◽  
Pia Åkerfeldt ◽  
Farnoosh Forouzan ◽  
Fredrik Svahn ◽  
Yuan Zhong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cryogenic Temperature ◽  
Room Temperature ◽  
Mechanical Performance ◽  
Microstructural Characterization ◽  
Tensile Tests ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
Temperature Range ◽  
Aerospace Applications

Laser powder bed fusion (L-PBF) has attracted great interest in the aerospace and medical sectors because it can produce complex and lightweight parts with high accuracy. Austenitic stainless steel alloy 316 L is widely used in many applications due to its good mechanical properties and high corrosion resistance over a wide temperature range. In this study, L-PBF-processed 316 L was investigated for its suitability in aerospace applications at cryogenic service temperatures and the behavior at cryogenic temperature was compared with room temperature to understand the properties and microstructural changes within this temperature range. Tensile tests were performed at room temperature and at −196 °C to study the mechanical performance and phase changes. The microstructure and fracture surfaces were characterized using scanning electron microscopy, and the phases were analyzed by X-ray diffraction. The results showed a significant increase in the strength of 316 L at −196 °C, while its ductility remained at an acceptable level. The results indicated the formation of ε and α martensite during cryogenic testing, which explained the increase in strength. Nanoindentation revealed different hardness values, indicating the different mechanical properties of austenite (γ), strained austenite, body-centered cubic martensite (α), and hexagonal close-packed martensite (ε) formed during the tensile tests due to mechanical deformation.

Fatigue responses of cracked Ti/APC-2 nanocomposite laminates at elevated temperature

2019 ◽  
Vol 54 (13) ◽  
pp. 1705-1715
Author(s):  
MHR Jen ◽  
GT Kuo ◽  
YH Wu ◽  
YJ Chen
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Composite Laminates ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Cyclic Tests ◽  
Constant Length ◽  
Nano Powder ◽  
Strength And Stiffness ◽  
Inclined Angle

The mechanical properties and fatigue responses of Ti/APC-2 neat and nanocomposites with inclined single-edged cracks due to tensile and cyclic tests at elevated temperature were investigated. Two types of composite laminates [Ti/(0/90)s/Ti] were fabricated with and without (W/WO) nanoparticles SiO2 of optimal 1 wt.%. The geometry and dimensions of specimens were L × W × t = 240 × 25 × 1.55 mm3. The cracks were of constant length 3 mm and width 0.3 mm. The inclined angles were 0°, 45°, and 60°. Both the tensile and cyclic tests were conducted at elevated temperatures 25℃ (RT), 100℃, 125℃, and 150℃. From the tensile tests we obtained the load vs. displacement curves for both types of laminates with varied inclinations at elevated temperatures. Next, we received the applied load vs. cycles curves for the same laminates with inclined cracks at the corresponding temperature due to cyclic tests. According to the experimental data of both tensile and cyclic tests the mechanical properties, such as strength, stiffness, and life, decreased as the temperature rises. The greater the inclined angles were, the greater the strength and stiffness were. Similarly, the fatigue life was in the same trend. However, the effect of inclined angle on mechanical properties was more strong than those of temperature. The mechanical properties of nanocomposite laminates were higher than those of neat composite laminates, but not significant. The main reason was that the enhancement of spreading nano-powder silica on the laminate interfaces did not effectively eliminate the stress intensity at the crack tip locally.

scholarly journals A Study of Some Mechanical Properties of Composite Materials with a Dammar-Based Hybrid Matrix and Reinforced by Waste Paper

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1688
Author(s):  
Marius Marinel Stănescu ◽  
Dumitru Bolcu
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Epoxy Resin ◽  
Volume Ratio ◽  
Tensile Tests ◽  
Sem Analysis ◽  
Waste Paper ◽  
Hybrid Resin ◽  
Natural Resin ◽  
Tensile Response

When obtaining environment-friendly hybrid resins made of a blend of Dammar natural resin, in a prevailing volume ratio, with epoxy resin, it is challenging to find alternatives for synthetic resins. Composite materials reinforced with waste paper and matrix made of epoxy resin or hybrid resin with a volume ratio of 60%, 70% and 80% Dammar were studied. All samples obtained have been submitted to tensile tests and Scanning Electron Microscopy (SEM) analysis. The tensile response, tensile strength, modulus of elasticity, elongation at break and the analysis of the fracture surface were determined. The damping properties of vibrations of bars in hybrid resins and in the composite materials under study were also examined. The mechanical properties of the four types of resins and of the composite materials were compared. The chemical composition for a hybrid resin specimen were obtained using the Fourier Transformed Infrared Spectroscopy (FTIR) and Energy, Dispersive X-ray Spectrometry (EDS) analyzes.

Mechanical Properties of Ramie Fiber Woven Composites under Biaxial Tensile Loadings

2011 ◽  
Vol 331 ◽  
pp. 65-68
Author(s):  
Ge Wang ◽  
Fu Ming Chen ◽  
Hai Tao Cheng ◽  
Zi Xuan Yu ◽  
Ze Hui Jiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Phenolic Resin ◽  
Natural Fiber ◽  
Woven Composites ◽  
Ramie Fiber ◽  
Test Analysis ◽  
Linear Elastic ◽  
Water Based ◽  
Negative Effect

The objective of this work was to use a novel 3-D test analysis system for evaluating the mechanical properties of the natural fiber fabric composites under biaxial loads. Composites with three resin matrices (water-based epoxy resin, isocyanate resin, phenolic resin) were investigated, and strain filed were characterized by using the digital speckle correlation. The water-based epoxy resin plate and isocyanate resin plate demonstrated a characteristic of orthotropy and elastoplasticity, while the phenolic resin board revealed linear elastic and brittle-fracture simultaneously at X,Y-axial. Dissimilarities of biaxial load value were related to the orthotropy of composite structure, and load changes in fracture direction had a negative effect on the other directions at breaking moment. The degrees of dropping presented a positive correlation with the load values at rift direction. Under the linear elastic stage, the value of load and average strain at Y-direction were larger than that under X-direction within the same testing area. The strain-filed at X/Y-direction provided by isocyanate and phenolic resin plates illustrated a more smooth change than that of the water-based epoxy resin plate.

Assessment of GFRP Mechanical Properties in Order to Determinate Suitability for UAV Components

2020 ◽  
Vol 834 ◽  
pp. 57-66
Author(s):  
Mihaela Raluca Condruz ◽  
Alexandru Paraschiv ◽  
Andreea Deutschlander ◽  
Ionel Mîndru
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Low Velocity Impact ◽  
Small Range ◽  
Low Velocity ◽  
Damage Degree ◽  
Aerial Vehicle ◽  
Twill Weave

Mechanical properties of several composite materials were assessed in order to establish their suitability for unmanned aerial vehicle components manufacturing. The materials under evaluation consisted in E-glass fiber (satin/twill weave) impregnated with polyester, respective epoxy resin. The study was focused on two mechanical tests: low-velocity impact and tensile tests. Based on the results obtained, it was observed that configurations reinforced with twill weave presented higher tensile strength compared with satin reinforced configurations. Moreover, they presented a lower damage degree in case of impact tests. It was concluded that fabric quality has a considerable influence on the impregnation process and on the composite material mechanical properties. In the present case, the twill weave impregnated with epoxy resin can be used to manufacture small range UAV components.

Fatigue Response of Hybrid Ti/APC-2 Nanocomposite Laminates with Single-Edged Cracks

2013 ◽  
Vol 592-593 ◽  
pp. 425-428
Author(s):  
Ming Hwa R. Jen ◽  
Che Kai Chang ◽  
Bo Cyuan Lin
Keyword(s):  
Mechanical Properties ◽  
Crack Length ◽  
Composite Laminates ◽  
Residual Life ◽  
Tensile Tests ◽  
Cyclic Tests ◽  
Paris Law ◽  
Modified Method ◽  
Longitudinal Stiffness ◽  
Static Tensile

The aims of this study are to fabricate Ti/APC-2 hybrid composite laminates with and without (W/WO) nanoparticles and investigate the mechanical properties of laminates with single-edged cracks due to both tensile and cyclic tests. The mechanical properties such as ultimate tensile strength and longitudinal stiffness of original composite laminates W/WO nanoparticles were first obtained from the static tensile tests. However, the load-displacement diagrams were plotted for the crack laminates. The constant stress amplitude tension-tension cyclic tests were conducted to receive the S-N curves and fatigue data. The ultimate strengths for both Ti/APC-2 composite laminates W/WO nanoparticles were very close at varied crack length. Ti/APC-2 cross-ply nanocomposite laminates had better fatigue resistance than that of laminates without nanoparticles. The longer the crack length is, the more their properties are reduced. Also, the values of fracture toughness of both hybrid cracked laminates W/WO nanoparticles were obtained by rule of mixtures and found acceptable. Finally, in predicting crack growth rate and residual life, instead of commonly used Paris Law for metals, the modified method was adopted for hybrid cracked laminates. The prediction is not satisfactorily acceptable, even if most results are in good agreement with empirical data.

Applied Research of the Flexible Epoxy Resin Curing Agent

2012 ◽  
Vol 535-537 ◽  
pp. 2499-2502
Author(s):  
X. Wang ◽  
S. R. Zheng ◽  
R. M. Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Fracture Surface ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Applied Research ◽  
Curing Agent ◽  
Structural Adhesives ◽  
Resin Curing ◽  
The Impact

Epoxy resin structural adhesives modified by flexible curing agent. Dependening on the mechanical properties of epoxy resins on the flexible curing agent content was studied. The impact fracture toughness was discussed in terms of fracture surface fractography.

scholarly journals The Effect of UV Exposure on the Service-life of Thermochromic Microcapsules Integrated into the Epoxy Matrix

2021 ◽  
Author(s):  
Olga BULDERBERGA ◽  
Andrey ANISKEVICH
Keyword(s):  
Mechanical Properties ◽  
Service Life ◽  
Epoxy Resin ◽  
Epoxy Matrix ◽  
Uv Light ◽  
Colour Change ◽  
Critical Time ◽  
Tensile Tests ◽  
Uv Exposure ◽  
Exposure Effect

The effect of ultraviolet (UV) exposure on the service-life of thermochromic microcapsules integrated into the epoxy matrix was investigated. The microcapsules of the formaldehyde shell contain the core of thermochromic leuco dye. Seven sets of epoxy resin samples filled with concentrations from 0 to 10 wt.% of microcapsules were investigated. The composite samples were exposed to UV for approximately 1000 h. For the quantitative evaluation of colour change under UV, a fast and simple original procedure based on samples’ image treatment was developed. With the exposure time intervals of 50 h, samples were taken out from the UV light chamber to evaluate the exposure effect on their reversible thermochromic ability and mechanical properties. Periodical evaluation of the UV light effect on mechanical properties during the exposure was performed by microhardness tests. Tensile tests of the samples till the fracture were performed every 200 h. The critical time under the exposure of the UV lamp that destroys the reversible thermochromic reaction of the microcapsules was defined as 200 h. At the same time, it has been found that the mechanical properties of the epoxy resin under the same UV source were not strongly affected after 1000 h of irradiance and changed in the frame of ~ 10 %.

scholarly journals Mechanical Behavior of Natural Fiber Composite Material

2021 ◽  
Author(s):  
Vikas Ghanwat ◽  
Jivan Mule ◽  
Saurabh Telore ◽  
Vijay Bhosale ◽  
Sudarshan Patale
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Composite Laminates ◽  
Fiber Length ◽  
Strain Energy ◽  
Natural Fiber ◽  
Fiber Composite ◽  
Natural Fibers ◽  
Industrial Applications ◽  
Coir Fiber

The use of natural fibers as reinforcement in polymeric composites is increasing thanks to the improvements in properties that fibers can provide to the merchandise. Composites materials were prepared by compression molding technique with hand layup process. Treatment of fiber with 2% NaOH was carried out in order to improve the interfacial bonds between fiber and matrix leading to better mechanical properties of the spathe-fiber-reinforced composite laminates. Filler loading as 5% by volume of coir fiber or epoxy resin composites have been formulated. The fiber length was chosen as 5mm, 10mm & 15mm and the ratio of epoxy resin: hardener was maintained as 10:0.8. A total three plates with dimension as 300 mm х 300 mm х 4 mm were produced and specimens as per the varied ASTM standard were tested to determine the ultimate tensile strength, strain energy, flexural strength, strain energy and micro hardness value for different configuration. It was observed that the lastingness of epoxy resin/ coir fiber composites was maximum at 15mm fiber length (16.27 N/mm2). The charpy notch impact strength was also maximum at 15mm fiber length (10.87 kJ/m2). The results show good mechanical properties and hint us as a replacement for conventional materials in industrial applications.

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