Applied Mechanics and Materials Vols. 670-671

Abstract: Seismic while drilling (SWD) technology, taking advantage of the vibration signal generated during the drill bit breaking rocks in drilling operations, has been used in the seismic explorations. Since the energy of signals produced by the seismic origin is weak while the noise jamming in the drilling site is strong, the signal-to-noise ratio (SNR) of collected SWD data is usually fairly low. In this paper, we focused on improving the SNR of SWD data via adjusting the impact energy of drilling tools. Based on the explanation of the working principle of SWD systems, the energy formation modes of three kinds of drilling tools were discussed. It was safe to expect that the hydraulic torque impactor could be applicable to improve the SNR of SWD data in evidence.

Abstract: The hollow Be rotor is grinded by the four-shaft-ball lapping machine, it has been repeated grinded to reach the accuracy requirement. The eccentric distance of rotor is measured by gas floating method. Actual measurements found that repeated measurement of the balancing cycle change a little during the rough finish and semi finishing stage while it changes a lot in the finish machining stage. This paper established the rotor balance equation of gas floating that is solved by Matlab software, and draw the curve of motion of the rotor changing along with time, analyze the motion curve to draw a conclusion that the starting conditions of finish machining stage have large influence on balancing cycle.

Abstract: In this study, an effective independence-improved modal strain energy (EI-IMSE) method is proposed for the optimal sensor placement (OSP) problem in the field of the structural health monitoring and moving force identification. The improved modal strain energy (IMSE) is used to modify optimal sensor placement results obtained by the effective independence (EI) method. The EI-IMSE OSP method is verified by some numerical simulations on a 2D planar truss bridge model. Based on the criteria of modal assurance criterion (MAC), trace of fisher matrix, matrix condition number, and the least mean square error, the EI-IMSE OSP method is assessed through comparing with those of EI, EI-driving point residue (EI-DPR), EI-average driving DOF velocity (EI-ADDOFV), and EI-average acceleration amplitude (EI-AAA). The illustrated results show that the proposed EI-IMSE OSP method is feasible with a higher accuracy.

Abstract: With the development of wearable computing, wireless communication and artificial intelligence technology, the physiological monitoring systems for homecare applications achieved more and more attention. It is a challenge to design a fully integrated circuit satisfying the requirements of wearable biosensor system, such as small size, low power consumption, wireless transmission, and high signal noise rate (SNR). Based on these considerations, we recently developed a fully-integrated circuit for a wearable biosensor system to measure multiple vital signs in real time, meanwhile, we adopted FIR notch filter to remove the 50Hz power line interference and used cubic spline interpolation to reduce baseline drift noise. The experimental results showed that this wearable system ran well, which could be applied for real-time and ubiquitous healthcare in daily life.

Abstract: There are many inconvenience in measuring the diameter of blind and deep holes. The measurement device can hardly stretch into the bottom. The paper is about a capacitive probe measurement system, the whole equipment includes capacitive probe sensor, the measured hole, precision drive part, two-dimensional micro-positioning platform. A simulation analysis was done for the structural parameters, and the eccentricity between the probe and the measured hole, then a reliable measurement results were obtained.

Abstract: Accurate measurement and modeling of complex surface is the foundation to precisely evaluate the error of complex surface. According to the NURBS method for rebuilding complex surface, a sampling data automatic replenishment method based on neural network is proposed and the sampling data with high precision is acquired. By using bicubic NURBS surface fitting method, the complex surface is rebuilt precisely and efficiently.

Abstract: A material on-line identification system based on THz time-domain spectroscopy using VC was developed in this paper. The main functions including data reading, linear motor driving, the calculation of optical parameters, the display and management of curve, the management of interface, the analysis of historical data , the maintenance and updating of database, and on-line identification based on principal component analysis were realized. As the prototype of material detection application, the material whose corresponding type characteristic spectrum has already existed in the database could be well identified.

Abstract: The monitoring system of the firebrick lining state of the blast furnace devil is offered. The mathematical description, algorithm and program of calculation the temperature fields in any vertical and horizontal cross-section of the devil lining are developed with use of the indications of the temperature sensing transducer (to 1000) in the oven lining. The systems of gathering, processing and information transfer from the temperature transmitters to a program database are used. This monitoring system is established on five blast furnaces of metallurgical plants of China.

Abstract: A new approach for roundness (circularity) error evaluation based on the differential evolution (DE) algorithm is proposed.The mathematical model of the roundness error under the condition of the minimum zone is derived. The background and advantages of DE are introduced, the fundamentals and implementation techniques are also given.The approach is verified by two examples.Compared with other methods, the results show that the proposed method makes the roundness error evaluation more accurate.

Abstract: A micro-loading stiffness detection method for micro-miniature components with brittle and complicated structure has been proposed to achieve stiffness detection of silicon arm. This paper adopts the methord of combing finite element analysis and micro-loading experiment together. Finally, the paper analyzed the deviation of silicon arm’s stiffness values obtained by simulation and experiment, and comparatively analyzed the variation tendency of silicon arm’s stiffness value among different claws. Result shows: the silicon arm’s stiffness value and the stiffness variation tendency obtained by experiment agrees well with it which is obtained by simulation. It proves the stiffness detection method is reliable and rational to achieve the stiffness detection of silicon arm.