Reduction of thermal residual stress in carbon fiber aluminum laminates using a thermal expansion clamp

2011 ◽  
Vol 42 (8) ◽  
pp. 986-992 ◽  
Author(s):  
Jia Xue ◽  
Wen-Xue Wang ◽  
Yoshihiro Takao ◽  
Terutake Matsubara
Keyword(s):  
Residual Stress ◽  
Thermal Expansion ◽  
Carbon Fiber ◽  
Thermal Residual Stress

Electrical Conductivity of VGCF/ Aluminum Composites Fabricated by Electro Spark Sintering

2007 ◽  
Vol 561-565 ◽  
pp. 729-732 ◽  
Author(s):  
Gen Sasaki ◽  
Fumiaki Kondo ◽  
Kazuhiro Matsugi ◽  
Osamu Yanagisawa
Keyword(s):  
Electrical Conductivity ◽  
Residual Stress ◽  
Electrical Resistivity ◽  
Thermal Expansion ◽  
Carbon Fiber ◽  
Ultrasonic Vibration ◽  
Volume Fraction ◽  
Pure Aluminum ◽  
Average Diameter ◽  
Aluminum Powders

Vapor grown carbon fiber (VGCF) was sleaved in acetone with ultrasonic vibration. Then pure aluminum powders with 3 μm in average diameter was poured into VGCF containing acetone and mixed with ultrasonic vibration. The composites were fabricated by electro spark sintering. The strength, rigidity, electrical conductivity and microstructure of the composites was investigated. VGCF was distributed uniformly and no pores was observed in composite. As increasing the volume fraction of VGCF in composites, the strength of composites increased gradually but the elongation decreased. The electrical resistivity of the composites increased as increasing VGCF content, constantly. The theoretical resistivity of composites without residual stress is lower than that of experimental results. It seems that is caused by the high dislocation density and strain introduced by big difference of thermal expansion between VGCF and pure aluminum.

Thermal Residual Stress and Tensile Strength of UACS/Al Laminate with Different Slit Angles

2013 ◽  
Vol 750 ◽  
pp. 204-207
Author(s):  
Jia Xue ◽  
Wen Xue Wang ◽  
Yoshihiro Takao ◽  
Terutake Matsubara
Keyword(s):  
Residual Stress ◽  
Tensile Strength ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Tensile Tests ◽  
Thermal Residual Stress ◽  
Fiber Direction ◽  
Shift Method ◽  
Yielding Point

This paper focus on the investigation of tensile strength and thermal residual stress in UACS/Al laminates. The UACS (unidirectionally arrayed chopped strands) is made by cutting parallel slits on unidirectional carbon fiber prepreg. Thus all of the carbon fibers in the cut prepreg are 25 mm in length. Six cases of UACS prepregs are prepared with different slit angle θ, which is the angle between slit and fiber direction, including 5.7o, 11.3o, 16.7o, 31o, 45o and 90o. A UACS/Al laminate consists of one UACS layer with four UACS plies and two aluminum layers, such as [Al/UACS4/Al]. Four pieces of UACS prepreg with alternate slit angle [θ/-θ/θ/-θ] are stacked together in the same fiber direction. Then stacked UACS/Al laminate are cured using an autoclave. Tensile tests are performed to investigate the thermal residuals stress using the yielding-point-shift method. Experiment results show that thermal residual stress is reduced in the case of UACS/Al compared with conventional CFRP/Al. Among all the cases, specimen with slit angle of 11.3o is the most impressive one with 37.7% reduction of thermal residual stress.

Residual Stresses in Intrinsic UD-CFRP-Steel-Laminates - Experimental Determination, Identification of Sources, Effects and Modification Approaches

2015 ◽  
Vol 825-826 ◽  
pp. 369-376 ◽  
Author(s):  
Robert Prussak ◽  
Daniel Stefaniak ◽  
Christian Hühne ◽  
Michael Sinapius
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Tensile Strength ◽  
Epoxy Composite ◽  
Thermal Residual Stress ◽  
Fiber Metal Laminates ◽  
Fiber Metal ◽  
Impact Energies ◽  
The Impact ◽  
Specific Impact

This paper focuses on the reduction of process-related thermal residual stress in fiber metal laminates and its impact on the mechanical properties. Different modifications during fabrication of co-cure bonded steel/carbon epoxy composite hybrid structures were investigated. Specific examinations are conducted on UD-CFRP-Steel specimens, modifying temperature, pressure or using a thermal expansion clamp during manufacturing. The impact of these parameters is then measured on the deflection of asymmetrical specimens or due yield-strength measurements of symmetrical specimens. The tensile strength is recorded to investigate the effect of thermal residual stress on the mechanical properties. Impact tests are performed to determine the influence on resulting damage areas at specific impact energies. The experiments revealed that the investigated modifications during processing of UD-CFRP-Steel specimens can significantly lower the thermal residual stress and thereby improve the tensile strength.

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