Determination of Water Diffusion Coefficients and Dynamics in Adhesive/Carbon Fiber Reinforced Epoxy Resin Composite Joints

To determinate the water diffusion coefficients and dynamics in adhesive/carben fiber reinforced epoxy resin composite joints, energy dispersive X-ray spectroscopy analysis（EDX） is used to establish the content change of oxy- gen in the adhesive in adhesive/carbon fther reinforced epoxy resin composite joints. As water is made up of oxygen and hydrogen, the water diffusion coefficients and dynamics in adhesive/carben fiber reinforced epoxy resin composite joints can be obtained from the change in the content of oxygen in the adhesive during humidity aging, via EDX analy-sis. The authors have calculated the water diffusion coefficients and dynamics in the adhesive/carbon fiber reinforced epoxy resin composite joints with the aid of beth energy dispersive X-ray spectroscopy and elemental analysis. The de- termined results with EDX analysis are almost the same as those determined with elemental analysis and the results al- so show that the durability of the adhesive/carbon fther reinforced epoxy resin composite joints subjected to silane cou- pling agent treatment is better than those subjected to sand paper burnishing treatment and chemical oxidation treat- ment.

Toughness and Fracture Mechanism of Carbon Fiber Reinforced Epoxy Composites

The fracture toughness of carbon fiber reinforced epoxy composite(CFRP)was investigated through mode I and mode II shaped fracture system in this paper.A novel polyimide with trifluoromethyl groups and grafted nanosilica were used to modify epoxy resin.Effect of modified resin and unmodified resin on fracture toughness of CFRP was compared and discussed.Lay-up angles and thicknesses effects on fracture toughness of composites were also investigated.The fracture toughness of CFRP was obtained through double cantilever beam(DCB)and end notched flexure(ENF)tests.The results showed that the composites prepared by modified resin exhibited high fracture toughness compared with unmodified composites.The fracture toughness value of mode I increased from 1.83 kJ/m2 to 4.55 kJ/m2.The fracture toughness value of mode II increased from 2.30 kJ/m2 to 6.47 kJ/m2.

Degradation Behavior of Epoxy Resins in Fibre Metal Laminates Under Thermal Conditions

GLARE （glass fibre/epoxy reinforced aluminum laminate） is a member of the fiber metal laminate （FML） family, and is built up of alternating metal and fiber layers. About 500 m2 GLARE is employed in each Airbus A380 because of the superior mechanical properties over the monolithic Muminum alloys, such as weight reduction, improved damage tolerance and higher ultimate tensile strength. Many tons of new GLARE scraps have been accumulated during the Airbus A380 manufacturing. Moreover, with the increasing plane orders of Airbus A380, more and more end-of-life （EOL） GLARE scrap will be generated after retire of planes within forty years. Thermal processing is a potential method for the material recycling and re-use from GLARE with the aim of environmental protection and economic benefits. The current study indicatdes that thermal delamination is a crucial pre-treatment step for the GLARE recycling. The decomposition behavior of the epoxy resins at elevated temperatures was investigated by using the simultaneous thermal analysis, thermogravimetry analysis （TGA） and differential scanning calorimetry （DSC）. Based on the thermal analysis results, GLARE thermal delamination experiments at refined temperatures were carried out to optimize the treatment temperature and holding time.

A Comprehensive Review on Epoxy Biocomposites Based on Natural Fibers and Bio‑fillers: Challenges, Recent Developments and Applications

Natural fiber-reinforced polymers remained a hot topic of interest in material sciences over the last two decades.Such fibers are appealing in composite materials due to their renewability,low density,better specific strength,biodegradability,accessibility,and low cost.Polymers reinforced with natural fibers provide improved mechanical performance at a lower cost and could be the best alternative to synthetic fibers.Bio-fillers have gained much attention nowadays due to their cost-effectivity and the ability to modify base materials in the composite structure.Natural materials reinforced epoxy composites have a high capacity due to their eco-friendliness,economic feasibility,and technical viability.However,some parameters directly influence desired product performance.This review discusses various properties of natural fibers and their impact on the overall performance of natural fiber-based epoxy composites.It summarizes the recent research on natural fibers/bio-fillers reinforced epoxy biocomposites.

Prediction model for determining the optimum operational parameters in laser forming of fiber-reinforced composites

Composite materials are widely employed in various industries,such as aerospace,automobile,and sports equipment,owing to their lightweight and strong structure in comparison with conventional materials.I aser material processing is a rapid technique for performing the various processes on composite materials.In particular,laser forming is a flexible and reliable approach for shaping fiber-metal laminates(FML.s),which are widely used in the aerospace industry due to several advantages,such as high strength and light weight.In this study,a prediction model was developed for determining the optimal laser parameters(power and speed)when forming FML composites.Artificial neural networks(ANNs)were applied to estimate the process outputs(temperature and bending angle)as a result of the modeling process.For this purpose,several ANN models were developed using various strategies.Finally,the achieved results demonstrated the advantage of the models for predicting the optimal operational parameters.