Jiazhen Zhang

Compressive and flexural behavior of carbon fiber-reinforced PPS composites at elevated temperature

ABSTRACT The effect of temperature on the mechanical behavior of carbon fiber reinforced polyphenylenesulfide (PPS) composites was investigated by compressive and flexural tests from ambient temperature up to 150°C. The failure morphologies of the C/PPS composites were analyzed to identify the variation of failure modes. Related results showed that the mechanical behavior of C/PPS composites decreased severely with the increase of temperature due to the softening of matrix. The PPS resin film tensile test was carried out and the PPS matrix behavior was recognized as the main factor to dominate the mechanical behavior of composites under compressive/flexural loading at elevated temperatures. It can be found that there was an approximate linear relationship between the compression properties of C/PPS composites and the PPS matrix. The dependence of failure modes of composites on temperatures was closely related to the mechanical behavior of PPS matrix.

Effect of temperature and geometrical parameters on mechanical properties of pin-loaded fiber metal laminate joints

To investigate the effect of temperature and geometrical parameters on the mechanical properties of pin-loaded fiber metal laminate joints, experiments were performed by means of static tensile tests. The joints of varied width-to-diameter ratios (W/D = 2, 3, 4) and edge distance-to-diameter ratios (E/D = 1, 2, 3, 4) were experimentally investigated at room temperature. It was found that ultimate failure load increased with the increase of the ratio of W/D or E/D. The dominant failure mode was bearing failure. Shear-out and net-tension failures were more easily caused as the pin hole was located closer to the edge of the specimen. Also, to explore the effect of temperature on the bearing responses of fiber metal laminate joints, three typical joint configurations (W/D = 4, E/D = 4; W/D = 4, E/D = 1; and W/D = 2, E/D = 4) were tested at high temperature, which ranged from 40℃ to 120℃. The test results clearly show that failure loads of joint decrease with the increase of the test temperature. The failure modes of the fiber metal laminate joints were predominantly affected by high test temperatures. The present work provides supporting information for the design of the fiber metal laminate joints.

Experimental investigations on the tensile properties of notched and unnotched carbon woven-ply PPS laminates at different temperatures

The effect of temperature on the mechanical behavior of woven carbon fabric/polyethylene sulfide (CF/PPS) was investigated in this paper. Tensile tests were both conducted on notched and unnotched specimens at different temperatures (ambient, 95°C and 125°C), their strength and moduli were obtained and compared. The damage patterns of notched specimens were examined with the aid of optics. The results revealed that the strength of the two type of specimens present decline trend as temperature increases, while the modulus slightly increased at 125°C due to the cold crystallization. Obvious fiber bundles rotation and delaminations were observed in the damage patterns of notched specimens at elevated temperatures, which suggested the plastic deformation of matrix was enhanced and fiber matrix interface bonding strength was weakened. In addition, the high retention rate of strength and stiffness at 200°C indicated CF/PPS composite can be used as primary aircraft structures at elevated temperatures.The effect of temperature on the mechanical behavior of woven carbon fabric/polyethylene sulfide (CF/PPS) was investigated in this paper. Tensile tests were both conducted on notched and unnotched specimens at different temperatures (ambient, 95°C and 125°C), their strength and moduli were obtained and compared. The damage patterns of notched specimens were examined with the aid of optics. The results revealed that the strength of the two type of specimens present decline trend as temperature increases, while the modulus slightly increased at 125°C due to the cold crystallization. Obvious fiber bundles rotation and delaminations were observed in the damage patterns of notched specimens at elevated temperatures, which suggested the plastic deformation of matrix was enhanced and fiber matrix interface bonding strength was weakened. In addition, the high retention rate of strength and stiffness at 200°C indicated CF/PPS composite can be used as primary aircraft structures at elevated temperatures.

Notched behavior of hybrid glass/aluminum/titanium fiber metal laminates

A hybrid glass/aluminum/titanium fiber metal laminate (FML) based on the standard GLARE concept was proposed in present paper, and its notched behavior was investigated experimentally and numerically. Experimental results revealed that a special three-stage stress-stain curve was obtained by this reinforced GLARE, which was related to the transition of load bearing mechanism. As well as, improvements of notched strength and normalized notched strength were achieved benefiting from the high strength and ductile nature of titanium, where their maximum increments obtained at D/W=0.2 were 11.88% and 15.40%, respectively. In addition, numerical results indicated that the finite element model (FEM) predicted well the notched behavior of GLARE with incorporating the thermal residual stress effect. Moreover, the comparisons of internal energy and damage dissipation energy between standard GLARE and reinforced GLARE have facilitated in the understanding of reinforced effect of titanium. It is believed that the pre...