Reliability design of bolt fatigue strength of hollow axle in cylinder of ball grinder
As to the connecting bolt of hollow axle in cylinder of ball grinder, its failure and stress distribution was analyzed, and its load distribution was calculated. As a result, the calculation method of reliable degree of fatigue strength was obtained. It is proved by an example that the method is reliable and has applying value.
Effect of the Hole on the Tensile Fatigue Properties of CFRP Laminates
The current study assessed the effect of a bolt hole on tensile fatigue properties of CFRP laminates. Two specimens, i.e. [(0/90)3]S, [(0/45/90/–45)2]S, were analyzed using a finite element method and were experimentally tested for cases, both with and without a hole, whose diameter corresponded to 0.12 times the specimen width. Delamination positions predicted by a 3-dimensional static finite element analysis were matched well to those observed by an ultrasonic imaging system in the middle of fatigue test. A hole whose diameter corresponds to 0.12 times the specimen width caused the fatigue strength to decrease by 9% and 11% under 5 Hz loading frequency, and by 22% and 25% under 10 Hz loading frequency for [(0/90)3]S and [(0/45/90/–45)2]S, respectively. Because the decrease in sectional area due to the hole was normalized in calculation of the tensile strength, a stress concentration around the hole is believed to induce the strength degradation of fatigue specimens. From the finite element analyses, the stress concentration factor around a hole was expected as 8.8 and 9.5 for [(0/90)3]S and [(0/45/90/–45)2]S, respectively.
Analytical behavior of frames with steel beams to concrete-filled steel tubular column
Abstract This paper reports the mechanism of composite frames with steel beams connected to concrete-filled square hollow section (SHS) columns. Detailed analysis was carried out on longitudinal stress in steel beams, axial stress distribution in concrete, and concrete stress along the column height and at the connection panel. Parametric studies were conducted to investigate the influence of axial load level, beam-to-column linear stiffness ratio on the structural behavior of composite frames. Simplified hysteretic lateral load ( P ) versus lateral displacement ( Δ ) models are proposed for such composite frames.