A novel rule-based model for multi-stage multi-product scheduling problem(MMSP)in batch plants with parallel units is proposed.The scheduling problem is decomposed into two sub-problems of order assignment and order s...A novel rule-based model for multi-stage multi-product scheduling problem(MMSP)in batch plants with parallel units is proposed.The scheduling problem is decomposed into two sub-problems of order assignment and order sequencing.Firstly,hierarchical scheduling strategy is presented for solving the former sub-problem,where the multi-stage multi-product batch process is divided into multiple sequentially connected single process stages,and then the production of orders are arranged in each single stage by using forward order assignment strategy and backward order assignment strategy respectively according to the feature of scheduling objective.Line-up competition algorithm(LCA)is presented to find out optimal order sequence and order assignment rule,which can minimize total flow time or maximize total weighted process time.Computational results show that the proposed approach can obtain better solutions than those of the literature for all scheduling problems with more than 10 orders.Moreover,with the problem size increasing,the solutions obtained by the proposed approach are improved remarkably.The proposed approach has the potential to solve large size MMSP.展开更多
This paper presents a customized simulation system for analyzing welding temperature field, which is based on Finite elementary Analysis software MSC. Marc. The system has the functions of robustly hexahedral meshing,...This paper presents a customized simulation system for analyzing welding temperature field, which is based on Finite elementary Analysis software MSC. Marc. The system has the functions of robustly hexahedral meshing, automated loading of dynamic heat source models for various welding methods and convenient post-processing for welding temperature field. A gene unit algorithm is presented to achieve robust simulation for assembled structure. High order routine method is used to generate various customized routines robustly, which includes Fortran subroutines for welding heat source, Marc command routines for automated modeling, and python subroutines for post-processing etc. With the system, simulation of welding temperature fields can be easily conducted with simple operations.展开更多
基金Supported by the National Natural Science Foundation of China(21376185)
文摘A novel rule-based model for multi-stage multi-product scheduling problem(MMSP)in batch plants with parallel units is proposed.The scheduling problem is decomposed into two sub-problems of order assignment and order sequencing.Firstly,hierarchical scheduling strategy is presented for solving the former sub-problem,where the multi-stage multi-product batch process is divided into multiple sequentially connected single process stages,and then the production of orders are arranged in each single stage by using forward order assignment strategy and backward order assignment strategy respectively according to the feature of scheduling objective.Line-up competition algorithm(LCA)is presented to find out optimal order sequence and order assignment rule,which can minimize total flow time or maximize total weighted process time.Computational results show that the proposed approach can obtain better solutions than those of the literature for all scheduling problems with more than 10 orders.Moreover,with the problem size increasing,the solutions obtained by the proposed approach are improved remarkably.The proposed approach has the potential to solve large size MMSP.
基金This work is supported by the National Natural Science Foundation of China under contracts 50904038 and 51175253.
文摘This paper presents a customized simulation system for analyzing welding temperature field, which is based on Finite elementary Analysis software MSC. Marc. The system has the functions of robustly hexahedral meshing, automated loading of dynamic heat source models for various welding methods and convenient post-processing for welding temperature field. A gene unit algorithm is presented to achieve robust simulation for assembled structure. High order routine method is used to generate various customized routines robustly, which includes Fortran subroutines for welding heat source, Marc command routines for automated modeling, and python subroutines for post-processing etc. With the system, simulation of welding temperature fields can be easily conducted with simple operations.
