Computer-Aided Design (CAD) and Finite Element Analysis (FEA) of Functionally-Graded-Material (FGM) objects are generally regarded as separate domains of interest in CAD and Computer-Aided Engineering (CAE) community. Such a separation of CAD modeling and FEA of FGM objects makes it cumbersome and tedious for both designers and engineers to exchange the necessary information in the entire design process. Without appropriate CAD models, complex material distributions can hardly be represented and the FGM objects under examination remain simple in material variations (e.g. unidirectional gradations). With CAD modeling tools only, the end users are still uncertain whether or not the designed objects can really meet the functional requirements in terms of structural, thermal or other prescribed properties. This paper proposes a systematic approach to integrate these domain-dependent design tools in FGM object design. Integrated solutions to CAD modeling and property analysis of FGM objects are utilized to design complicated (bi-directional or even tri-variate) FGM objects. Complex FGM distributions are encoded into the proposed Heterogeneous Feature Tree (HFT) structure; and the material compositions of a given point of interest are interrogated from the CAD models at runtime. Integrated FEA of FGM objects are then carried out by establishing a link between the proposed CAD modeler (CAD4D) and a commercial FEA package (COMSOL Multiphysics). Four different (three unidirectional and one bidirectional) FGM objects are modeled with traditional analytic function based approaches and the proposed methods. Under the same thermal and mechanical conditions, the properties of each model are compared in terms of temperature fields, residual thermal stresses and the strain energy densities. Results show that the proposed approach can facilitate the design of complex FGM objects in a systematic way. 相似文献
Palladium‐catalyzed cycloaromatization of N‐acyl‐2‐aminobiaryls, through a sequence of ortho C−H bond activation/alkyne insertion/meta C−H bond activation/alkyne insertion, was developed. An efficient synthesis of multiaryl‐substituted naphthalenes, N‐[2‐(5,6,7,8‐tetraarylnaphthalen‐1‐yl)aryl]acetamides, was demonstrated using molecular oxygen as the sole oxidant. Furthermore, through Buchwald's synthetic protocol, two compounds were converted into corresponding fluorescent carbazoles in 30–40% yield by intramolecular C−N bond formation.
A novel azathia-crown ether dye was synthesized and characterized and its binding ability with metal ions was investigated via UV–vis spectroscopy. When a series of alkali-metal, alkaline earth metal and transition metal ions were mixed with the dye in acetonitrile, only Hg2+ induced a large blue shift from 478 nm to 369 nm corresponding to a distinct color change from red to yellow, which made it possible to distinguish Hg2+ from other metal ions by the naked-eye. The excellent Hg2+-selectivity of the dye was attributed to the formation of a 1:2 dye:Hg2+ coordination complex which was demonstrated by means of a Job's plot. 相似文献
Film cooling performance about a row of dual-fanned holes with injection angles of 30°, 60 ° and 90° were experimentally investigated at blowing ratios of 1.0 and 2.0. Dual-fanned hole is a novel shaped hole which has both inlet expansion and outlet expansion. A transient thermochromic liquid crystal technique was used to reveal the local values of film cooling effectiveness and heat transfer coefficient. The results show that injection angles have strong influence on the two dimensional distributions of film cooling effectiveness and heat transfer coefficient. For the small injection angle of 30 degree and small blowing ratio of 1.0, there is only a narrow spanwise region covered with film. The increase of injection angle and blowing ratio both leads to the enhanced spanwise film diffusion, but reduced local cooling ability far away from the hole. Injection angles have comprehensive influence on the averaged film cooling effectiveness for various x/d locations. As injection angles are 30 and 60 degree, two bands of high heat transfer coefficients are found in mixing region of the gas and coolant. As injection angle increases to 90 degree, the mixing leads to the enhanced heat transfer region near the film hole. The averaged heat transfer coefficient increases with the increase of injection angle. 相似文献