Fatigue Fracture and Residual Life of Inclined Single-edge-cracked Ti/APC-2 Hybrid Composite Laminates

• Main Authors: Hui-chi Chou, 周惠琪
• Other Authors: Ming-Hwa R Jen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/95e8p3

碩士 === 國立中山大學 === 機械與機電工程學系研究所 === 103 === This thesis aims to investigate the mechanical properties and fatigue characteristics with various crack length and different inclined angles of Ti/APC-2 hybrid composite laminates due to the tensile tests and fatigue tests. From the empirical data of tensile and fatigue tests, we obtain the important results as follows. First, the value of KI is decreased with the increase of inclined angles, where is the value of KII is maximal when the inclined angle is 45ﾟ. Second, the shorter the cracks, the faster residual strength declines; and so on. Third, the value of stress intensity factor is increased with the finite width function , F(a/w) .Finally, the inclined angles are, the fatigue residual life of the longer crack length (6.0mm) is generally better than other crack length(1.5mm,3.0mm) specimens. The load-displacement diagrams of various crack length and different inclined angles specimens after the static tensile tests were plotted. In fatigue tests, were adopted the constant stress amplitude tension-tension cyclic tests, and the load-control mode at a sinusoidal loading wave with frequency of 5Hz and stress ratio R=0.1. From fatigue tests we obtained fatigue data, and plotted the load vs. cycles diagrams with different inclined single-edged cracks. The Ti/APC-2 laminates were three-layered laminates, with a piece of 0.55 mm thickness APC-2 lay-ups covered by two pieces of 0.5 mm titanium alloy sheets. APC-2 laminates were stacked according to cross-ply [0/90]s sequences. Using chromic acid anodic method to surface treat titanium, the chromic acid anodic method can perfectly bond the titanium sheets and APC-2. The curing process were used to fabricate Ti/APC-2 hybrid composite laminates.The inclined single-edged cracks were cut by electrical discharge machine , the crack lengths were 1.5, 3.0, 6.0 mm and the inclined angles were 15ﾟ,30ﾟ,45ﾟ. And the MTS 810 material testing machine was used to conduct all the static tensile tests and fatigue tests.