Applied Mechanics and Materials Vol. 742

Abstract: A series of accelerated full-scale tests on rigid pavement were conducted to evaluate the concrete slab curling effects on the pavement design. Data from deflection sensors and embedded strain gages were acquired and analyzed along with the observed performance data. The collected data can be used for identifying the slab corner cracking and potentially giving the slab curling amount. Traffic tests were simulated using the finite element method in three dimensions and compared with sensor readings. A comparison of maximum tensile stresses between the curling slab and flat slab was performed. It was found that the critical stresses are located near the longitudinal joint in the curling model, the same as the distress observation of concrete slab.

Abstract: The low conductivity material such as cancellous bone, cortical bone tissue and soft tissue is the mainly content in the spine. And the improvements on distinguishing the low conductivity material can make a contribution to the spinal fixation surgery process, and protect the patient from spine incident trauma injury during internal fixation prosthetics with implanting pedicle screws. As a result the low conductivity material detection is of great importance in biomedicine study. According to the magnetic property difference of different low conductivity material, an eddy current detection method based on GMR sensor which is proposed in this paper. Compared with coil sensor in traditional non-contact detecting system, GMR sensors have advantages of higher sensitivity, higher precision, better linearity and better stability. Based on this methods, this paper introduces a low conductivity material detection probe. Several experiments indicate that this detection method can detect the low conductivity material NaCl solution with conductivity of 0.128 S/m, whose electrical conductivity matches that of biological tissue. This results lay a solid foundation on the biological tissue detection research.

Abstract: The device errors of a rotating-wave-plate-based polarization measurement system can be mainly categorized as the angle error of the polarization prism, the fast axis angle error of wave-plate and the retardation error. By applying Fourier analysis to solve Stokes vectors, we obtain the formulas to calculate the three errors mentioned above, using linear 0° and 45° polarized light to illuminate the system for the error solving. We analyze the measurement errors of the degree of polarization, the polarization purity and the intensity of polarization state, under certain simulation conditions. The results show that after the calibration, the measurement accuracy is improved. Finally, we analyze the effects of the angle error of the linear polarized light used for calibration to the measurement of the three parameters.

Abstract: Basing on the Image-Pro plus (IPP) technique, a kind of groove filter rod characteristic parameters (such as groove depth, channel ventilation area, number of grooves) measurement system was build. Method: put 5 groups of standard channel ventilation area-known groove rods and 10 pre-cut self-made groove filters under the microscope with the groove sides up, adjust the intensity of the light and the focal length, take the pictures of all. Use IPP to measure all the parameters, and MINTAB to analyze the accuracy and precision of the IPP system. Results: (1) the IPP system is convenient to operate, easy to use and fast to measure the characteristic parameters such as channel ventilation areas, groove depth as well as groove numbers of the groove filters. (2) the measurements for the channel ventilation area, groove depth doesn't exist linear bias. The channel ventilation area precision index GageR&R = 24.66 < 30, and groove depth precision index GageR&R = 26.40 < 30, which means measurement precision is good.( 3)The manual measurement mode and automatic measurement mode of IPP system in regard to the measurement results bear no significant difference (P > 0.05), and can be chosen for different needs. The measuring method provides help in the research of groove filters rod’ tar-reducing mechanism as well as in the increase of production process control capacity.

Abstract: The aim of this paper is to determine the efficacy of the ring-shaped array used for imaging the objects inside the array. Hyperbola algorithm and ellipse algorithm which are conventionally used in the field of guided wave for locating the defects are developed and combined here to extract the image. Meanwhile, much more phase information is added in this process. Fan-shaped ultrasound radiation is generated separately by the 45 rectangular ultrasonic transducers which are circular embedded in the wall of a container. The time of flight data and the attenuation data are obtained and stored in the A-scan wave of each receiving transducer, subsequently, they are applied for reconstructing the image of all tested objects. The validity of the combined measuring method with phase information is demonstrated by imaging the distributed polyurethane objects.

Abstract: By comparing the normalized radar backscatter cross sections (NRCS) and significant wave height detected by the Jason-1 altimeter with high wind speeds data, an empirical algorithm valid for wind speeds larger than 20 m s^-1 is developed and proposed. The study shows that the Root Mean Square Error (RMSE) and average relative error of the new algorithm are 5.44m s^-1 and 16.5%, suggesting increased accuracy by including significant wave height in the retrieval algorithm. Therefore, the proposed algorithm, suitable for retrieving sea surface wind speeds in typhoon and other strong wind conditions, could be treated as supplementary algorithm to the Jason-1 operational algorithm.

Abstract: This paper introduces the theory of eddy current pulsed thermography and expounds the research status of eddy current pulsed thermography in application and information extraction. Thermographic signal reconstruction, pulsed phase thermography, principal component analysis were introuduced in this paper and listed some fusion multiple methods to acquire information from infrared image. At last, it summarizes research progress, existing problem and deelopment of eddy current pulsed thermography.

Abstract: For multi-target radar track Extraction, the paper proposed a multi-regional threshold method, by setting a plurality of parameters threshold, to determine whether the next time point falls within the threshold based on relevant criteria, then to build the track; further proposed satisfaction law, track was established by the relevant observation points, which the satisfaction function is defined between the associated trace points and set it to the threshold, Through the case of simulation, the model results are given in comparison.

Abstract: In order to distinguish underwater targets, the method of target depth resolution urgently need to be developed. Matched field processing (MFP) is a passive detection method and it can be used to distinguish two targets at different depth. In this paper single vertical array MFP simulation has been done for targets depth resolution while they have same distance and azimuth in ocean acoustic field and the results show that the resolution is basically correspond to theoretical value.

Abstract: Many Factors influencing the testing accuracy are discussed according to the differences between the testing data of most of the domestic anti-force rolling brake testing platform. We try to get the theoretical analysis and be proved by experiment through the mechanical model. We focus on some respects just as attachment coefficient, tire pressure, vehicle moving and direction displacement which influencing the testing accuracy of the anti-force rolling brake testing platform.