An improved multidirectional velocity model was proposed for more accurately locating micro-seismic events in rock engineering. It was assumed that the stress wave propagation velocities from a micro-seismic source to...An improved multidirectional velocity model was proposed for more accurately locating micro-seismic events in rock engineering. It was assumed that the stress wave propagation velocities from a micro-seismic source to three nearest monitoring sensors in a sensor's array arrangement were the same. Since the defined objective function does not require pre-measurement of the stress wave propagation velocity in the field, errors from the velocity measurement can be avoided in comparison to three traditional velocity models. By analyzing 24 different cases, the proposed multidirectional velocity model iterated by the Simplex method is found to be the best option no matter the source is within the region of the sensor's array or not. The proposed model and the adopted iterative algorithm are verified by field data and it is concluded that it can significantly reduce the error of the estimated source location.展开更多
The principle of sonic wave measurement was introduced, and cumulative damage effects of underground engineering rock mass under blasting load were studied by in situ test, using RSM-SY5 intelligent sonic wave apparat...The principle of sonic wave measurement was introduced, and cumulative damage effects of underground engineering rock mass under blasting load were studied by in situ test, using RSM-SY5 intelligent sonic wave apparatus. The blasting test was carried out for ten times at some tunnels of Changba Lead-Zinc Mine. The damage depth of surrounding rock caused by old blasting excavation （0.8-1.2 m） was confirmed. The relation between the cumulative damage degree and blast times was obtained. The results show that the sonic velocity decreases gradually with increasing blast times, hut the damage degree （D） increases. The damage cumulative law is non-linear. The damage degree caused by blast decreases with increasing distance, and damage effects become indistinct. The blasting damage of rock mass is anisotropic. The damage degree of rock mass within charging range is maximal. And the more the charge is, the more severe the damage degree of rock mass is. The test results provide references for researches of mechanical parameters of rock mass and dynamic stability analysis of underground chambers.展开更多
Computer-integrated manufacturing (CIM) and revers e engineering (RE) have changed drastically the concept of product re-design, pla nning and manufacture of components. However, the main problems currently facing the...Computer-integrated manufacturing (CIM) and revers e engineering (RE) have changed drastically the concept of product re-design, pla nning and manufacture of components. However, the main problems currently facing the developers of reverse engineering system, is the time consuming digitis ation of 3D data and the conversion of large amounts of data into a concise and manageable format and linking it to a CAD/CAM system. Automated 3-D profile gen eration, measurements and inspection of manufactured component represents one of the important functions in reverse engineering and in the improvements in produ ct quality in rapid product developments. The paper presents a novel methodology for the development of a reverse enginee ring technique for use in the rapid product development in a CIM environment . The system developed provides integration, data capture and manipulation, dat a transfer between a CAD, CAM, Computer-aided inspection (CAI) and a 3-D profi le scanning system. An efficient scanning strategy has been developed for scann ing and surfaces data acquisition. The products were scanned using a laser scann ing system with a dedicated scan control card and the associated software packag es. A versatile rig was developed for the ease of data gathering of the profile scanning process. The surface data collected was then used to build a mathematic al surface model, which was then used to develop a virtual 3-D model of the pro duct. The resulting surface model provides the geometrical input to the subseque nt machining operation using either a CNC system or other manufacturing operatio n e.g. dies casting/mould casting etc. The prototypes developed were inspected u sing a state-of-the art CNC-CMM that was integrated to the CAD/CAM system. Si nce the scanning/digitised data captured by laser scanning probes requires no ma nual editing, significant time saving over most non-contact probe systems was a chieved. Since the creation of an accurate CAD model of a redesigned component o r a prototype constitute a major element of the total turnaround time; maximum r eturn can be achieved by increasing the efficiency of the redesigning process. T he paper also outlines with a case study the application of the developed system . The system developed offers the flexibility of using the concept of reverse en gineering of a variety of components with the complimentary facility of integrat ion between CAD/CAM Computer-aided Inspection (CAI) systems and a scanning syst em. The developed reverse engineering application in an integrated manufacturing system can increase the consistency, improve cost-efficiency, reduce produ ct turn around and skill levels required to redesign, reengineer and prototyping components and products.展开更多
基金Project(IRT0950)supported by the Cheung Kong Scholars and the Development Plan of Innovative Team,ChinaProject supported by China Scholarship Council
文摘An improved multidirectional velocity model was proposed for more accurately locating micro-seismic events in rock engineering. It was assumed that the stress wave propagation velocities from a micro-seismic source to three nearest monitoring sensors in a sensor's array arrangement were the same. Since the defined objective function does not require pre-measurement of the stress wave propagation velocity in the field, errors from the velocity measurement can be avoided in comparison to three traditional velocity models. By analyzing 24 different cases, the proposed multidirectional velocity model iterated by the Simplex method is found to be the best option no matter the source is within the region of the sensor's array or not. The proposed model and the adopted iterative algorithm are verified by field data and it is concluded that it can significantly reduce the error of the estimated source location.
基金Project (50490272) supported by the National Natural Science Foundation of ChinaProject(040109) supported by the Doctor Degree Paper Innovation Engineering of Central South University
文摘The principle of sonic wave measurement was introduced, and cumulative damage effects of underground engineering rock mass under blasting load were studied by in situ test, using RSM-SY5 intelligent sonic wave apparatus. The blasting test was carried out for ten times at some tunnels of Changba Lead-Zinc Mine. The damage depth of surrounding rock caused by old blasting excavation （0.8-1.2 m） was confirmed. The relation between the cumulative damage degree and blast times was obtained. The results show that the sonic velocity decreases gradually with increasing blast times, hut the damage degree （D） increases. The damage cumulative law is non-linear. The damage degree caused by blast decreases with increasing distance, and damage effects become indistinct. The blasting damage of rock mass is anisotropic. The damage degree of rock mass within charging range is maximal. And the more the charge is, the more severe the damage degree of rock mass is. The test results provide references for researches of mechanical parameters of rock mass and dynamic stability analysis of underground chambers.
文摘Computer-integrated manufacturing (CIM) and revers e engineering (RE) have changed drastically the concept of product re-design, pla nning and manufacture of components. However, the main problems currently facing the developers of reverse engineering system, is the time consuming digitis ation of 3D data and the conversion of large amounts of data into a concise and manageable format and linking it to a CAD/CAM system. Automated 3-D profile gen eration, measurements and inspection of manufactured component represents one of the important functions in reverse engineering and in the improvements in produ ct quality in rapid product developments. The paper presents a novel methodology for the development of a reverse enginee ring technique for use in the rapid product development in a CIM environment . The system developed provides integration, data capture and manipulation, dat a transfer between a CAD, CAM, Computer-aided inspection (CAI) and a 3-D profi le scanning system. An efficient scanning strategy has been developed for scann ing and surfaces data acquisition. The products were scanned using a laser scann ing system with a dedicated scan control card and the associated software packag es. A versatile rig was developed for the ease of data gathering of the profile scanning process. The surface data collected was then used to build a mathematic al surface model, which was then used to develop a virtual 3-D model of the pro duct. The resulting surface model provides the geometrical input to the subseque nt machining operation using either a CNC system or other manufacturing operatio n e.g. dies casting/mould casting etc. The prototypes developed were inspected u sing a state-of-the art CNC-CMM that was integrated to the CAD/CAM system. Si nce the scanning/digitised data captured by laser scanning probes requires no ma nual editing, significant time saving over most non-contact probe systems was a chieved. Since the creation of an accurate CAD model of a redesigned component o r a prototype constitute a major element of the total turnaround time; maximum r eturn can be achieved by increasing the efficiency of the redesigning process. T he paper also outlines with a case study the application of the developed system . The system developed offers the flexibility of using the concept of reverse en gineering of a variety of components with the complimentary facility of integrat ion between CAD/CAM Computer-aided Inspection (CAI) systems and a scanning syst em. The developed reverse engineering application in an integrated manufacturing system can increase the consistency, improve cost-efficiency, reduce produ ct turn around and skill levels required to redesign, reengineer and prototyping components and products.
