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2017, 37(6): .

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2017, 37(6): .

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Research on Perforation Limit Thickness of Low Carbon Steel Plates Impacted Normally by Tungsten Spheres

XU Yu-xin, REN Jie, WANG Shu-shan

2017, 37(6): 551-556. doi:10.15918/j.tbit1001-0645.2017.06.001

Abstract(1148) PDF(1180)

Abstract:
Perforation limit thickness of low carbon steel plates impacted normally by tungsten spheres was studied. Based on six-projectile test data analysis method, ballistic limit velocity and the range of perforation limit thickness were obtained by using tungsten spheres withΦ6.0 mm (93 W),Φ7.0 mm(93 W),Φ6.0 mm(95 W) andΦ7.5 mm(95 W) to impact Q235A steel plates with 6 different thicknesses. Numerical simulation with the same experimental conditions was conducted using Autodyn-3D software. After the reliability of simulation model was verified, perforation limit thickness range was obtained by simulation and the energy transformation rule of the penetration process was analyzed. The calculation model for perforation limit thicknesses of steel plates impacted normally by tungsten spheres was established based on the principle of energy conservation. The calculation results of the perforation limit thicknesses of Q235A steel plates struck normally by tungsten spheres withΦ6.0 mm (93 W),Φ7.0 mm(93 W),Φ6.0 mm(95 W) andΦ7.5 mm(95 W) were respectively 16.95, 19.17, 17.30 and 21.50 mm. The error between the experiment results and the range obtained from simulation analysis is no more than 10%. This research provides basic data and the method for the design of the kill element of blast-fragmentation warhead.

Experimental Study on Ignition Effects of Fuel-Filled Tank Impacted by Reactive Material Projectile

XIAO Yan-wen, XU Feng-yue, ZHENG Yuan-feng, YU Qing-bo, WANG Hai-fu

2017, 37(6): 557-561. doi:10.15918/j.tbit1001-0645.2017.06.002

Abstract(1297) PDF(955)

Abstract:
Ballistic impact experiments were conducted to investigate the ignition effects of a fuel-filled tank impacted by high-density pressed and sintered PTFE/Al/W reactive material projectiles. The experimental results show that, with the mass and size of projectiles fixed, when impacting a fuel-filled tank, the reactive projectile has a stronger capacity in igniting the tank than the steel projectile; the ignition behavior of reactive material projectiles by impacting a fuel-filled tank not only varies with impact velocity, but also is significantly influenced by impact position. Based on experimental results, the mechanisms of the influences of impact velocity and position on rupture and ignition of tanks with different amounts of fuel were analyzed. The results show that, reactive projectiles, through the combined effects of kinetic energy and chemical energy released during explosion, remarkably increase the damage to the fuel tank, improving the ejection and atomization of fuel. On the other hand, the duration and expansion region of the ignition source produced by deflagration reaction of reactive materials are greater. Thus reactive projectiles' capacity to ignite fuel is enhanced significantly.

Compact Analytical Model of Squeeze-Film Damping Considering Slip Boundary Conditions in Perforated MEMS Structures

GAO Chun-hui, GAO Shi-qiao, JIN Lei, LIU Hai-peng, NIU Shao-hua

2017, 37(6): 562-566. doi:10.15918/j.tbit1001-0645.2017.06.003

Abstract(879) PDF(839)

Abstract:
A compact analytical model of squeeze-film damping in perforated MEMS plates was presented. The compact analytical model took several factors into consideration, including the rarefaction of the air flow,the pressure loss caused by perforating and the air shear force formed on the inner wall. The perforated plate was divided into several identical circular cells. The pressure distribution in each circular cell was obtained through a modified Reynolds equation. The rarefaction effect of air flow was explained by considering the slip boundary conditions. The loss of pressure because of perforating was determined according to the conservation of air flow. The compact analytical model was compared with Kwok's analytical model, Veijola's analytical model and the experiment results obtained by Pasquale respectively in order to verify the correctness of the theoretical model. The results indicate that the compact analytical model presented in this paper computes more accurately than Kwok's model and more conveniently than Veijola's model.

Evaluation of Anchorage Quality of Rock Bolts Using Ultrasoinc Guided Wave

HE Wen, WANG Cheng, SHI Wen-fang, NING Jian-guo, ZHAO Kui

2017, 37(6): 567-572,578. doi:10.15918/j.tbit1001-0645.2017.06.004

Abstract(1119) PDF(1169)

Abstract:
Low frequency ultrasonic longitudinal guided waves were applied to inspect the anchorage quality of rock bolts. The effects of modulation wave type and signal's cycle number on signal spectrum were firstly analyzed, and sinusoidal waves modulated by Hanning window were selected for guided wave testing. Then longitudinal guided waves with frequencies 20~100 kHz reflected from the upper interface of grouted rock bolts were numerically simulated. Based on theoretical analysis and experimental investigation, a new method was proposed so that the debond length of grouted rockbolts could be determined by the time difference between bolt end reflected wave and upper interface reflected wave, and then the bonding compactness of a grouted rock bolt was calculated. The results show that guided wave reflection coefficient from the upper interface of grouting rock bolts decreases with the increase of frequency. The experimental results of guided wave reflection coefficient vary considerably from simulation ones, which is due to the transducer's resonant frequency and the energy loss between the transducer and the bolt end. The testing results of bonding compactness agree well with theoretical results.

Design of Effective Working Diameters of Rotating Detonation Engine

LIU Yan-ming, Qing Yang, Wang Cheng, JIANG Chun-hui

2017, 37(6): 573-578. doi:10.15918/j.tbit1001-0645.2017.06.005

Abstract(1044) PDF(1653)

Abstract:
One-step Arrhenius reaction model was used with no consideration of the effect of viscosity, heat transmission and diffusion on flow for mixtures of H₂/Air to simulate two-dimensional rotating detonation engine(RDE) to research on RDE's effective diameter range. The inviscid flux was discreted with fifth-order WENO scheme, and the time integration was performed with three-order Runge-Kutta Scheme. The results show that the critical diameter of RDE is 0.51lin specific conditions, wherelrefers to the axial length, only when the diameter is larger than the critical diameter can RDE work properly. As the diameter increases, the thrust, specific impulse, detonation wave height and the wave propagation velocity increase gradually. The upper limit of RDE's diameter is about 2.80l, which comes from Lagrange quadratic interpolation. The effective diameter range of RDE(takinglas the length unit) in this specific condition is 0.51 ≤L^*≤ 2.80.

Numerical Simulation and Experimental Investigation on New Type Jetting Projectile Charge

XU Wen-long, WANG Cheng, XU Bin, HU Ping

2017, 37(6): 579-583,589. doi:10.15918/j.tbit1001-0645.2017.06.006

Abstract(1258) PDF(1344)

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A new structure of jetting projectile charge (JPC) was proposed to solve the deficiencies of existing JPC, such as lower velocity and utilization ratio of explosive energy. The forming process of the new type JPC and the influence of truncate height of liners and additional structures on the JPC formation were studied based on Autodyn. An optimized JPC featuring high velocity and small velocity gradient was put forward and tested by experiments. The numerical results are in good agreement with the experimental ones, which indicates that the calculation method, material model and related parameters are reasonable. The correctness of the numerical simulation was also verified. The research results provide a certain reference value to further optimization of the design of JPC.

Measurement of Micro-Vibration Based on Laser Self-Mixing Interference

LUO Hui-fu, WANG Yang-hong, ZHU Wei, CHEN Qiang-hua, WU Huan, MA Bin-wu, ZHAO Zhen-feng

2017, 37(6): 584-589. doi:10.15918/j.tbit1001-0645.2017.06.007

Abstract(1365) PDF(1378)

Abstract:
Laser self-mixing method is very suitable for the measurement of small vibration because of its high precision, simple optical path and better collimation. However, in the measurement of micro-vibration, because of the small amplitude of the object, the low coefficient of the surface and the small amplitude of the measured signal, it caused a great difficulty for the demodulation of the signal with the unobvious inclination of the signal waveform due to the optical feedback. A pre-feedback mirror was added in the self-mixing interference light path to form a feedback optical path system, which could enhance the measurement signal to 2~4 times. At the same time, the frequency and amplitude demodulation algorithm named "fundamental formula-extreme point" was derived and a model was built to realize the demodulation of the signal. The theoretical analysis and experimental results show that the error of the frequency is less than 2.5%, and the error of the amplitude is less than 5%.

The Definition of Long Steep Downgrade Based on Driver Behavior

HU Jiang-bi, LI Xiao-yu, LUO Shao-jian, WANG Rong-hua, GAO Xiao-juan

2017, 37(6): 590-594. doi:10.15918/j.tbit1001-0645.2017.06.008

Abstract(1159) PDF(1213)

Abstract:
It is often meet in the process of designing the expressway in the mountainous area to design long steep downgrade section. But the current route design specification doesn't have the definition criterion of long steep downgrade sections. Starting from the driver's driving behavior and driving needs, the running speed was taken as the macro performance of driving behavior to analyze the performance of driving behavior in this article. Some experimental data were collected from the real vehicle test on 20 truck drivers in the mountainous expressway long steep downgrade section. By analyzing the data, the correlation between the speed with the average longitudinal slope and the longitudinal slope length was found, and a prediction model was established for the truck operating speed. And then the maximum longitudinal slope length under the condition of different longitudinal slope was got at 60 km/h design speed. The conclusion can provide a reference for the designing and operation management of expressway long steep downgrade in mountainous area.

Fast Prediction Method for GNSS Satellite Visibility Determination in Urban Canyons

CAI Xi, LIU Song-ling, XU Cheng-dong

2017, 37(6): 595-601. doi:10.15918/j.tbit1001-0645.2017.06.009

Abstract(1080) PDF(1104)

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Urban canyons always negatively affect the performance of global navigation satellite system (GNSS). Using 3D city models to predict GNSS satellite visibility is one of the most common methods concerning urban canyons. However, due to the extremely huge data of 3D city models, calculations involved in the prediction of GNSS visibility can be very time-consuming. To solve this problem, a method was proposed that was capable of quickly predicting the existence of urban buildings blocking GNSS satellite signals. This method reduced the burden of calculation and shortened the time for calculating by analyzing the direction of normal vector of the triangular patch, the relative positions of the triangular patch and the user, and the occlusion relation between two adjacent moments. A simulation of this method was conducted. The results show that the intersection calculation counts is only 7.21% of the traditional method, and the computing time 22.38%, while the average relative error is just 1.89%. In conclusion, this new method has a higher computing efficiency and higher accuracy.

Profit Allocation Rule Based on Job Positions for Sequencing Games

ZHOU Yi-yuan, ZHANG Qiang

2017, 37(6): 602-606,612. doi:10.15918/j.tbit1001-0645.2017.06.010

Abstract(799) PDF(712)

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As for cooperative games concerning sequencing based on total weighted completion time, according to the contributions of jobs, profit allocation rule based on job positions was introduced. The core relationship between this rule and sequencing games was discussed. And the dummy property and disconnected property were also discussed. Average loss property was proposed. A special allocation, which is based on job positions, is axiomatized through efficiency and the average loss property.

Harmonic Wave Radar Seeker Target Recognition Algorithm Based on Polarization Invariant

HE Chang-jian, MENG Xiu-yun

2017, 37(6): 607-612. doi:10.15918/j.tbit1001-0645.2017.06.011

Abstract(834) PDF(681)

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Traditional FFT recognition algorithm based on harmonic wave scattering coefficient could not effectively distinguish the whole trajectory harmonic wave scattering properties of targets. To solve this problem, target recognition algorithm based on polarization invariant was proposed. The target's harmonic wave scattering coefficient was deduced according to its semiconductor model. The target's harmonic wave scattering coefficient was estimated using Kalman filter. With the estimated coefficient as the diagonal element of the unitary matrix, target harmonic wave polarization scattering matrix and harmonic wave power matrix were built. Simulation results were obtained through the harmonic wave scattering polarization algorithm of different targets. The results show that this algorithm can reflect the whole trajectory harmonic wave scattering properties of the target compared with FFT recognition algorithm based on harmonic wave scattering coefficient and that the value of the target's harmonic wave polarization scattering matrix and the trajectory of the power matrix could be used as effective characteristic variables for target recognition.

A Calibration Method Based on Surrogate Model for Simulation Models with Multi-Variant Outputs

QIAN Xiao-chao, LI Wei, YANG Ming

2017, 37(6): 613-619. doi:10.15918/j.tbit1001-0645.2017.06.012

Abstract(864) PDF(1040)

Abstract:
To solve the calibration problem of simulation model with multi-variant and different kinds of output data, a calibration method based on optimization and surrogate model was presented. To acquire the output of simulation model with both of aleatory and epistemic uncertainty, an uncertainty propagation method based on two stage nested latin hyper sample(LHS) was introduced. Then, a coherence measurement method based on data feature was used to measure the coherence of the simulation and reference outputs. Furthermore, a stochastic Kriging model was applied to build the data coherence surrogate model of the simulation output and epistemic uncertainty sample. And based on the surrogate model, the calibration results were obtained via the genetic algorithm. Finally, the method was validated in the application.

Fast CU Depth Decision and Direction Mode Decision Algorithm for HEVC Intra Coding

MA Yue, LIU Zhao-yi, ZHONG Shun-an, REN Shi-wei

2017, 37(6): 620-624. doi:10.15918/j.tbit1001-0645.2017.06.013

Abstract(961) PDF(1379)

Abstract:
High efficiency video coding is the latest video coding standard. It adopts a quad-tree structure and 35 direction modes to improve coding performance, however, is at the expense of high coding complexity. To speed up the encoder, a fast CU depth decision method was proposed in this paper. Firstly, a spatial correlation between the current CU and its neighboring CUs was utilized to predict the depth for the current CU, accordingly a quick decision could be made for the division mode of CU. And then, the direction mode decision algorithm was implemented by a rate-distortion optimization process, skipping some unimportant direction modes. Test results show that the proposed algorithm can achieve 53% coding time saving on average, and can keep a better coding quality, while BDBR is only 1.17%.

Risk Analysis and Detection on Communication with Intents in Android Applications

YANG Tian-chang, CUI Hao-liang, NIU Shao-zhang, HUANG Zhen-peng

2017, 37(6): 625-630,636. doi:10.15918/j.tbit1001-0645.2017.06.014

Abstract(1086) PDF(1608)

Abstract:
In order to detect the security defects caused by the intent communication in Android applications, a detection method was proposed based on the combination of dynamic test and static analysis. In static analysis phase, the internal and external intentioned components in application were detected to estimate the risk of being hijacked according to the designed method. For components requested by the Intent with Extras attribute, sensitive data and privilege leakage were checked by stain tracking analysis at last. In dynamic testing phase, according to the Intents detected in the static analysis phase, the formatted test data were constructed for the Fuzzing test and the test instructions were sent to the application installed on the test platform. And the execution logs were collected and used to determine whether a risk of service denial exists. Experimental results show that, the detection method can detect effectively and comprehensively the Intent-based security defects.

Analysis on Random Vibration Response of Photoelectric PCB

CHENG Lei, ZHOU De-jian, WU Zhao-hua

2017, 37(6): 631-636. doi:10.15918/j.tbit1001-0645.2017.06.015

Abstract(833) PDF(2734)

Abstract:
The influence of random vibration on optoelectronic PCB reliability was analyzed. In the product conceptual design stage, a three-dimensional finite element model of photoelectric PCB was established. Photoelectric PCB mode parameters which obtained under the four-point fixed condition were studied. Result shows that the frequency difference between the 1st and the 2nd order, or between the 4th and the 5th order is small, and the multi-order resonance phenomenon is likely to occur between the adjacent orders. The random vibration response analysis under dynamic environment which defined by GJB 150.16-86 was carried out using the Block Lanczos method. Especially, the research focused on the impact of random vibration load on optoelectronic PCB, including the warpage of optoelectronic PCB, solder joints reliability, optical coupling efficiency and optical fiber reliability.

Three-Phase Face Recognition Algorithm via Locally Frontal Face Synthesis and Two-Phase Face Recognition

ZHAO Qing-jie, QI Hui, ZHANG Yu, WANG Hao

2017, 37(6): 637-643. doi:10.15918/j.tbit1001-0645.2017.06.016

Abstract(1221) PDF(1140)

Abstract:
Two-phase test sample representation algorithm (TPTSR), which is robust to interference such as occlusion and noise, performs well in face recognition without pose variation. However, its recognition rate will decline when the face pose varies dramatically. To solve this problem, a three-phase test sample representation algorithm was proposed. The first was frontal face synthesizing was a frontal face with small horizontal deflection angle was synthesized using view-library and proposed frontal face synthesizing algorithm. Thus, a frontal face was synthesized as the new test sample. The second was training sample selecting phase,Mtraining samples that make the most contribution were selected to represent the new test sample. The third was decision and recognition phase, a face was recognized using theMtraining samples. Experiments on some publicly available face recognition benchmarks demonstrate that the proposed 3PTSR algorithm outperforms the state-of-the-art methods in challenging conditions, especially for the face with various poses.

An Improved BTV-Based Image Deblurring Algorithm Based on a Low-Resolution Image Constraint

LU Lu, JIN Wei-qi, WANG Xia, DUN Xiong, TIAN Li

2017, 37(6): 644-649,655. doi:10.15918/j.tbit1001-0645.2017.06.017

Abstract(953) PDF(1372)

Abstract:
Multi-frame image super-resolution reconstruction (SRR) algorithms are typically divided into two steps,data fusion and image deblurring,in order to reduce computational complexity. However, some small or weak detail signals lost in the data fusion step cannot be recovered by the conventional image deblurring method. Therefore, a low resolution image constraint (LRIC) was introduced into the traditional deblurring optimization based on the bilateral total variation (BTV) regularization, and then a new deblurring method named BTV-LRIC was obtained in the LRIC based deblurring optimization using gradient descent method. The experiments show that, for data fusion images with different image contents or obtained using different data fusion methods, BTV-LRIC is superior to the TV and BTV method in terms of both visual perception and objective scores.

A Rapid Detection Method of Mycotoxins Using Double Color Sensors

CHEN Guo-hua, WANG Yu-jie, DONG Yi-yang, ZHANG Ai-jun, YIN Xue-ting, XING Jian

2017, 37(6): 650-655. doi:10.15918/j.tbit1001-0645.2017.06.018

Abstract(1064) PDF(1065)

Abstract:
To improve the detection efficiency and reduce the testing cost in available mycotoxins detection methods, a rapid detection method was proposed and a color detection system was designed. In this detection system, two color sensors were applied, one was for the measurement of the color information in the sample solution,the other was for the measurement of the white balance parameters of the ambient light in real time to realize the dynamic white balance and make the color detection system be adaptive to the changing ambient light. Finally, the linear relationship between the mycotoxins concentration and theRGBvalues of the sample solution was established. The experimental results show that, the relative standard deviation(RSD) of the sampled data is less than 5%, and the relative error(RE) of the concentration calculated by the linear relationship and the actual concentration of the sample is less than 7%, both of which meet the laboratory requirements of precision and accuracy respectively. Compared with the common detection methods, this method is fast, convenient, and reduces the detection cost as well.

Quasi-Static Analysis and Energy Collection Experiment on a Low-Frequency Piezoelectric Energy Harvester

ZHANG Guang-yi, GAO Shi-qiao, LIU Hai-peng, LI Ping, NIU Shao-hua

2017, 37(6): 656-660. doi:10.15918/j.tbit1001-0645.2017.06.019

Abstract(973) PDF(1136)

Abstract:
For the low frequency vibration energy in daily environment, based on the cantilever beam piezoelectric structure with low frequency, the harvester's quasi-static vibration model was built, and corresponding simulation and experiments were conducted to verify the model. The research results show that the results of the mathematical model are in good agreement with the results of the simulation and experiments. When the structure was in a state of resonance (58.9 Hz), and the acceleration was 10 m/s², the open circuit output voltage could reach 86.3 V and the maximum output power 27.5 mW. In addition, to solve the energy storage problem of the piezoelectric harvester, LTC3588-1 chip was used to design the energy harvesting circuit. With the energy harvesting circuit, the charging test of the super-capacitor was conducted. The results show that it takes 6 000 s for the voltage of the 0.22 F 5 V super-capacitor to rise from 0 V to 3.6 V.

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