A new algorithm for the solution of under constraint graph in sketch drawing is put forward. The directed process of constraint graph is completed by picking concealed constraints of adjacent entities in sketch of few...A new algorithm for the solution of under constraint graph in sketch drawing is put forward. The directed process of constraint graph is completed by picking concealed constraints of adjacent entities in sketch of few or no dimensions. In this paper, the priority of concealed constraint is given by the different constraint types and constructing orders, and some more priority concealed constraints are forced into obvious ones by the need number of constraint for every node in constraint solution process.展开更多
The welding temperature field and deformation of parallel arrangement small-section rectangular tubes is calculated by using a non-contact model. After comparing the computed results with the experimentally measured r...The welding temperature field and deformation of parallel arrangement small-section rectangular tubes is calculated by using a non-contact model. After comparing the computed results with the experimentally measured results, it shows that there exist big errors when applying this model to the numerical simulation of small-section rectangular tube＇ s welding temperature field and deformation. Based on a simple analysis of the errors, a contact model is presented. The heat transfer and stress analysis between small-section rectangular tubes and clamping fixture are simulated by using direct constraints method, and then the laws of the temperature distribution, which coincide with experiment, are obtained. A further numerical analysis of the stress and deformation are made, it shows that a ＂T＂ shaped stress-field is formed in the vicinity of the weld. As the stress-field departs from the centroid of tubes＇, this leads to the small rectangular tubes not only have a longitudinal deflection, but also have a transverse bending and deformation.展开更多
文摘A new algorithm for the solution of under constraint graph in sketch drawing is put forward. The directed process of constraint graph is completed by picking concealed constraints of adjacent entities in sketch of few or no dimensions. In this paper, the priority of concealed constraint is given by the different constraint types and constructing orders, and some more priority concealed constraints are forced into obvious ones by the need number of constraint for every node in constraint solution process.
文摘The welding temperature field and deformation of parallel arrangement small-section rectangular tubes is calculated by using a non-contact model. After comparing the computed results with the experimentally measured results, it shows that there exist big errors when applying this model to the numerical simulation of small-section rectangular tube＇ s welding temperature field and deformation. Based on a simple analysis of the errors, a contact model is presented. The heat transfer and stress analysis between small-section rectangular tubes and clamping fixture are simulated by using direct constraints method, and then the laws of the temperature distribution, which coincide with experiment, are obtained. A further numerical analysis of the stress and deformation are made, it shows that a ＂T＂ shaped stress-field is formed in the vicinity of the weld. As the stress-field departs from the centroid of tubes＇, this leads to the small rectangular tubes not only have a longitudinal deflection, but also have a transverse bending and deformation.
