A layered simulation model with stairstep contour is built from AutoCAD through extruding each successive section contour having been compensated in dimensions to meet the application requirements of the RP part. In s...A layered simulation model with stairstep contour is built from AutoCAD through extruding each successive section contour having been compensated in dimensions to meet the application requirements of the RP part. In such a way the shape and size tolerance of the RP product could be verified beforehand promptly and precisely.展开更多
In this paper, an algorithm for simulating fluid flow and heat transfer for mold filling of shaped castings is presented. The main features of the algorithm include: 1) a simple but practical technique based on VOF me...In this paper, an algorithm for simulating fluid flow and heat transfer for mold filling of shaped castings is presented. The main features of the algorithm include: 1) a simple but practical technique based on VOF method to determine free surface, 2) an explicit scheme of enthalpy to solve the energy equation more efficiently, and 3) an effective treatment to modify the flux deviation due to pressure iteration. In order to verify these methods, well controlled experiments have been repeatedly done with both water analog and gray iron pouring experiments to record the flow patterns and temperature variations. The calculated results are in accordance with the experimental ones. For the applications, the simulated initial temperature distribution right after mold filling was used to analyse subsequent solidification and to predict shrinkage defects. Actual castings were poured and tested in a foundry plant. The reuslts show that the defects predication with considering fluid flow effects is more precise than that without considering the effects.展开更多
Methods for identifying sub-regional material parameters of concrete damsusing incomplete rnodal data are presented. With the measurements of the first frequency andincomplete mode shape, identification methods were b...Methods for identifying sub-regional material parameters of concrete damsusing incomplete rnodal data are presented. With the measurements of the first frequency andincomplete mode shape, identification methods were built by both the output error approach and theminimum deviation approach. The minimum deviation approach was introduced as physical constraints tothe output error approach, allowing the output error-minimum deviation coupled approach to bedeveloped. The simulated annealing-simplex shape algorithm was applied to solve the identificationmodels. Numerical simulations were carried out with noisy incomplete measurements to illustrate therobustness of the methods.展开更多
In order to determine artificial ventilated cavity shape and provide design reference for engineering applications, the shape of ventilated cavity and the drag of underwater body have been numerically simulated with c...In order to determine artificial ventilated cavity shape and provide design reference for engineering applications, the shape of ventilated cavity and the drag of underwater body have been numerically simulated with commercial code in this work. Empirical formulas between ventilated cavity shape and cavitation number are obtained under the conditions of zero incidence and similarity shapes of ventilated cavity and vapor cavity have been validated under the same cavitation number. In addition, the relations between change of cavitator incidence and cavity unsymmetry and the relations of between drag and cavity shape have been primarily analysed. Furthermore, the numerical results fit well with the experimental results.展开更多
基金Supported by College Science Foundation of Jiangsu(07KJB460113)
文摘A layered simulation model with stairstep contour is built from AutoCAD through extruding each successive section contour having been compensated in dimensions to meet the application requirements of the RP part. In such a way the shape and size tolerance of the RP product could be verified beforehand promptly and precisely.
文摘In this paper, an algorithm for simulating fluid flow and heat transfer for mold filling of shaped castings is presented. The main features of the algorithm include: 1) a simple but practical technique based on VOF method to determine free surface, 2) an explicit scheme of enthalpy to solve the energy equation more efficiently, and 3) an effective treatment to modify the flux deviation due to pressure iteration. In order to verify these methods, well controlled experiments have been repeatedly done with both water analog and gray iron pouring experiments to record the flow patterns and temperature variations. The calculated results are in accordance with the experimental ones. For the applications, the simulated initial temperature distribution right after mold filling was used to analyse subsequent solidification and to predict shrinkage defects. Actual castings were poured and tested in a foundry plant. The reuslts show that the defects predication with considering fluid flow effects is more precise than that without considering the effects.
文摘Methods for identifying sub-regional material parameters of concrete damsusing incomplete rnodal data are presented. With the measurements of the first frequency andincomplete mode shape, identification methods were built by both the output error approach and theminimum deviation approach. The minimum deviation approach was introduced as physical constraints tothe output error approach, allowing the output error-minimum deviation coupled approach to bedeveloped. The simulated annealing-simplex shape algorithm was applied to solve the identificationmodels. Numerical simulations were carried out with noisy incomplete measurements to illustrate therobustness of the methods.
文摘In order to determine artificial ventilated cavity shape and provide design reference for engineering applications, the shape of ventilated cavity and the drag of underwater body have been numerically simulated with commercial code in this work. Empirical formulas between ventilated cavity shape and cavitation number are obtained under the conditions of zero incidence and similarity shapes of ventilated cavity and vapor cavity have been validated under the same cavitation number. In addition, the relations between change of cavitator incidence and cavity unsymmetry and the relations of between drag and cavity shape have been primarily analysed. Furthermore, the numerical results fit well with the experimental results.
