Damping Capacities of B/Al Composite Subjected to Thermal-Mechanical Cycling

2007 ◽  
Vol 561-565 ◽  
pp. 679-682
Author(s):  
Yao Chun Qin ◽  
S.Y. He
Keyword(s):  
Temperature Interval ◽  
Logarithmic Decrement ◽  
Mechanical Loss ◽  
Mechanical Cycling ◽  
Present Test ◽  
Damping Behavior ◽  
Al Composite ◽  
Applied Stresses

The damping capacities of B/Al composite subjected to thermal-mechanical cycling (TMC) were studied. The damping capacities, including the mechanical loss Q-1 and the logarithmic decrement δ , increase with increasing the TMC cycles. The damping capacities of B/Al composite increase more greatly under the elevated applied stresses at the same temperature interval and cycles. After the TMC, the damping capacities can increase 10 times than that of as-fabricated B/Al composite. The damping behavior of B/Al composite under the present test condition is primarily associated with the interfacial degradation during the TMC.

Advanced Techniques for Determining High and Extreme High Damping: OMI - A New Algorithm to Compute the Logarithmic Decrement

2006 ◽  
Vol 319 ◽  
pp. 231-0 ◽  
Author(s):  
A. Stanislawczyk
Keyword(s):  
High Precision ◽  
Relative Error ◽  
Logarithmic Decrement ◽  
Mechanical Loss ◽  
Harmonic Oscillations ◽  
Experimental Conditions ◽  
Damping Materials

A new algorithm OMI (Optimization in Multiple Intervals) for the computation of the logarithmic decrement from exponentially damped harmonic oscillations is described. This method is shown to be effective and computationally compact for high damping materials. A comparison between the OMI algorithm and the four classical methods usually used in the computation of the logarithmic decrement is reported. The OMI algorithm yields high precision in the computation of the logarithmic decrement and the smallest dispersion of experimental points on the plots of mechanical loss spectra. The effect of the acquisition parameters and the experimental conditions on the results of computations of the logarithmic decrement and the relative error is discussed.

Microstructure and Mechanical Properties of B/Al Composite after Thermal-Mechanical Cycling

2005 ◽  
Vol 475-479 ◽  
pp. 889-892
Author(s):  
Yao Chun Qin ◽  
Shi Yu He ◽  
Dezhua
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Early Stage ◽  
Aluminum Matrix ◽  
Tensile Fracture ◽  
Dislocation Generation ◽  
Mechanical Cycling ◽  
Transmission Electron ◽  
Al Composite ◽  
Before And After

The mechanical properties of B/Al composite were measured at room temperature before and after thermal-mechanical cycling (TMC) in the temperature interval from –125°C to 125°C under constant stress of 30 MPa. The effects of TMC on microstructure and tensile fracture behavior of B/Al composite were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The fiber / matrix interfaces were degraded during TMC, the extent of which was enhanced with increasing the cycles, causing a measurable decrease of stageⅠmodulus of the B/Al composite. The TMC induced the dislocation generation in the aluminum matrix and the dislocation density increased with increasing the cycles. The tensile strength of the composites increased with the cycles in the early stage of TMC, but subsequently decreased after further TMC. The interfaces in the B/Al composite changed from the strongly-bonded toward the appropriately-bonded, and then to the weakly–bonded ones with increasing the cycles.

Effect of thermal-mechanical cycling on damping capacity of B/Al composite

2004 ◽  
Vol 39 (11) ◽  
pp. 3845-3847 ◽  
Author(s):  
Yaochun Qin ◽  
Shiyu He ◽  
Dezhuang Yang
Keyword(s):  
Damping Capacity ◽  
Mechanical Cycling ◽  
Al Composite
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