This paper presents experiments and models of a piezoelectric cantilever generator with a right-angle structure. Analysis shows that the extended part provides a large torque to the main beam, which can dramatically smoothen the strain distribution of the main beam. The auxiliary beam was fabricated with half the length of the main beam. When the auxiliary beam has a stiffness which is 0.02 times that of the main beam the piezoelectric element has a highly uniform strain distribution; in addition, its relative utilization efficiency (RUE) is 93% at the initial resonant frequency, whereas it is 50% for a conventional rectangular piezoelectric cantilever. The performances of three right-angle generators with auxiliary beams having different levels of stiffness, but constant-stiffness main beams are studied. The RUE of the piezoelements increases as the auxiliary beam’s stiffness decreases. A model based on the Rayleigh–Ritz method is established to demonstrate the principle of the strain-smoothing effect. The voltage and power outputs of the generators are measured. Finite element method simulations are also presented, and the result fits the experiments well.
The microstructure and wear behavior of Cu-TiC composite which prepared by spark plasma sintering (SPS) and mechanical alloying (MA) were discussed in this paper. X-ray diffraction patterns and scanning electronic microscopy (SEM) images indicate that TiC were formed during sintering process. The pin-on-disc wear test was carried. Confocal scanning laser microscope (CFSLM) images indicate that mechanical mixed layer appeared on the worn surface the mechanical mixed layer broken up when normal load reached 200N. The composites displayed excellent wear resistance with 2.38×10−5 mm3/Nm specific wear loss.
The oxidation behavior of two ductile cast irons was investigated in this paper. The alloys were a high Si-Mo ductile and a ductile Ni-Resist cast iron which were developed by FAW Foundry. Polished sections were exposed at temperatures between 800 °C and 1000 °C, mostly for 80h. It has been found that the property of oxidation resistance of ductile Ni-Resist cast iron is excellent or better than that of high Si-Mo ductile by comparison and analysis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.