Development of an Intelligent Knowledge Based System (IKBS) for forging die design

The work in this thesis is concerned with further development of an Intelligent Knowledge-Based System (IKBS) for forging die design. It follows on from initial work carried out at the School of Manufacturing and Mechanical Engineering. The main parts of the original design for the system are a sequence design program (SDP) for two and three dimensional parts, an interface program which can be connected to a finite-element program for metal forming simulation and a Control Module which supervises these two parts and co-ordinates their activities. Of these three modules, only the SDP and the Control Module existed when the current work was started. The purpose of the work reported here is to develop, improve and validate the original system. Among the five different families of components within the original IKBS, Stub Axles have been selected for the current research work. An interface program has been written which can generate a datafile for the available finite-element program (EPFEP3). This interface program inputs one preform stage as the geometry for mesh generation and the corresponding product stage in order to determine the boundary conditions. It also inputs the data within the SDP database for completing the other parts of the datafile. This program is efficient, rapid and user friendly and can easily be extended for the other families of components in the SDP. In the IKBS, when a new component is input to the system, each forming stage of the component should be compared with the same stage of the same family of all the components stored in the database. To do so, the significant processing and geometrical parameters and also their weighting effects should be input to the system. A new experimentally-based approach has been developed to obtain the weighting effects of the significant parameters. The weighting factors obtained are saved in the knowledge-base and have been shown to lead to the correct predictions when data for real forgings was used. The method for obtaining the weighting effects of the significant parameters can be extended to the other families of components within the IKBS. Programs have been written to perform computer-aided reasoning in the IKBS. In particular, recognising and extracting the values of the significant parameters of the operational sequence of a component, creating the IKBS database based on real data and performing the comparison procedure for a new component stage with those stored in the IKBS database

Scaling out parallel data stream access to a relational database

The rise of new applications requiring processing high volumes of continuous and real time data has created the demand for data stream management systems (DSMSs). Applications  using DSMSs often need to access historical data saved on disk to analyze, mine, and process streaming data. The historical data is persistent and often is very voluminous and is therefore  usually stored in a relational database. If this relational database is continuously accessed from the DSMS it will become a bottleneck of the system. The linear road benchmark (LRB) is a simulated data stream benchmark, which includes access to historical data stored on disk. If the query load per unit of time becomes too large the relational database access will become a bottleneck for the DSMS processing. In this thesis we scale out a relational DBMS storing the historical LRB data in order to eliminate this bottleneck. Experiments were done on LRB with access to a scaled out MySQL databases running on a single NUMA machine with 64 cores. Scaling out the relational database access is shown to make it possible to run LRB with L rating of 512 and beyond for only daily expenditure queries and L rating of 150 for all the LRB implemented in the DSMS SCSQ

Forming of micro gears by compressing a pure copper sheet through its thickness

Currently, micro gears are mostly fabricated by LIGA technology and micromachining. These processes have some limitations. Forming processes not only satisfy mass production and appropriate productivity rate but also present superior mechanical properties. A major problem preventing the bulk micro metal forming is the preparation of micro billets and their precise transfer between the forming stages. The purpose of this study is developing a method to form a micro gear without the need to a separate micro billet preparation. In this paper, pure copper sheets were compressed into the predetermined micro gear profiles though their thicknesses, so that there is no need for preparation of micro billets and also its troublesome transforming. The tests were performed at room temperature, in two cases of single extrusion process and extrusion-forging process. Micro gears with 6 teeth and 250μm in module were formed completely with good repeatability in both the cases. A major advantage of the proposed study compared with the blanking process is that, in blanking, the process is merely cutting the edges, while here the material fills the die by deformation. Thus, better mechanical properties will be achieved. Measuring the micro-hardness of the formed parts in comparison with raw material, verified this point. In general, the micro-hardnesses of combined extrusion-forging parts were higher than those of single extrusion ones in the same positions on the micro gears surface

Forming of micro gears by compressing a pure copper sheet through its thickness

Currently, micro gears are mostly fabricated by LIGA technology and micromachining. These processes have some limitations. Forming processes not only satisfy mass production and appropriate productivity rate but also present superior mechanical properties. A major problem preventing the bulk micro metal forming is the preparation of micro billets and their precise transfer between the forming stages. The purpose of this study is developing a method to form a micro gear without the need to a separate micro billet preparation. In this paper, pure copper sheets were compressed into the predetermined micro gear profiles though their thicknesses, so that there is no need for preparation of micro billets and also its troublesome transforming. The tests were performed at room temperature, in two cases of single extrusion process and extrusion-forging process. Micro gears with 6 teeth and 250μm in module were formed completely with good repeatability in both the cases. A major advantage of the proposed study compared with the blanking process is that, in blanking, the process is merely cutting the edges, while here the material fills the die by deformation. Thus, better mechanical properties will be achieved. Measuring the micro-hardness of the formed parts in comparison with raw material, verified this point. In general, the micro-hardnesses of combined extrusion-forging parts were higher than those of single extrusion ones in the same positions on the micro gears surface

Combined upper bound and slab method, finite element and experimental study of optimal die profile in extrusion

In this paper, a new combined upper bound and slab method is proposed for estimating the deformation load for cold rod extrusion of aluminum and lead in an optimum curved die profile. For the purpose of comparison, an optimum conical die that was already obtained by the authors, has also been selected and studied. The corresponding results have also been determined experimentally and by using the finite element software, ABAQUS. It is illustrated that the extrusion load in the optimum curved die during the deformation is considerably less than that in the optimum conical die.Peer reviewed: YesNRC publication: Ye

Investigation of a Modified Hydrodynamic Deep Drawing Assisted by Radial Pressure with Inward Flowing Liquid Process

Hydrodynamic Deep Drawing (HDDRP), the combination of hydroforming and conventional deep drawing, accommodates the advantages of the two processes. A technique, called HDDRP with inward flowing liquid, has been introduced based on the idea of insertion of radial pressure around the blank rim. The radial pressure created on the blank edge, can increase the drawing ratio. Thus, increasing the radial pressure to an amount greater than the cavity pressure, and independent control of these pressures is the basic idea of this research for forming cylindrical parts. To perform the experiments, two independent pumps were used to provide the two pressures independently. The pressure supply system and the die set were designed in a way that provides simultaneous control of the pressures throughout the process. Then, the effects of radial pressure paths on thickness distribution of cylindrical St13 cups were investigated. In addition, a comparison between HDDRP and HDDRP with inward flowing liquid processes has been performed experimentally. Results indicated that using a higher radial pressure than the cavity pressure and controlling their values at any moment of the process enhances the thickness distribution of the formed part in all regions

A hybrid approach based on numerical, statistical and intelligent techniques for optimization of tube drawing process to produced squared section from round tube

In the tube drawing process, there are a bunch of parameters which play key role in process performance. Thus, finding the optimized parameters is a controversial issue. Current study aimed to produce a squared section of round tube by tube sinking process. To simulate the process finite element method (FEM) was used. Then, to find a meaningful kinship between process input and output parameters the developed FE model was associated with the design of experiment based response surface methodology (RSM). The sufficiency of each model was checked by analysis of variances. Further, the SA (simulated annealing) was associated with RSM models to find the optimal solution regarding maximum thickness distributions and minimum force and dimensional error. Hereafter, for performing accurate optimization, the principal component analysis was used to find the appropriate weight factor of each response. The obtained results were in right agreement with those derived from simulation and confirmatory experiment

Investigation of a Modified Hydrodynamic Deep Drawing Assisted by Radial Pressure with Inward Flowing Liquid Process

Hydrodynamic Deep Drawing (HDDRP), the combination of hydroforming and conventional deep drawing, accommodates the advantages of the two processes. A technique, called HDDRP with inward flowing liquid, has been introduced based on the idea of insertion of radial pressure around the blank rim. The radial pressure created on the blank edge, can increase the drawing ratio. Thus, increasing the radial pressure to an amount greater than the cavity pressure, and independent control of these pressures is the basic idea of this research for forming cylindrical parts. To perform the experiments, two independent pumps were used to provide the two pressures independently. The pressure supply system and the die set were designed in a way that provides simultaneous control of the pressures throughout the process. Then, the effects of radial pressure paths on thickness distribution of cylindrical St13 cups were investigated. In addition, a comparison between HDDRP and HDDRP with inward flowing liquid processes has been performed experimentally. Results indicated that using a higher radial pressure than the cavity pressure and controlling their values at any moment of the process enhances the thickness distribution of the formed part in all regions