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2018, 38(6): .

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2018, 38(6): .

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Abstract:

Cavitation in Visco-Elastoplastic Material Under Thermal Shock

WU Pei-fei, SHANG Xin-chun

2018, 38(6): 551-556. doi:10.15918/j.tbit1001-0645.2018.06.001

Abstract(874) PDF(577)

Abstract:
The thermal cavitation of visco-elastoplastic material was analyzed theoretically. The mathematical model for void growth in an infinite visco-elastoplastic medium under thermal shock was built, taking into account the ideal incompressible plasticity with big deformation and viscoelasticity with small deformation. The technique of integration was adopted to obtain analytic solutions to void growth. And the nonlinear evolution equation of the moving interface was derived. Numerical examples were presented to analyze the influence of thermal shock temperature, heating rate and viscosity on the moving interface and void growth. Moreover, the critical temperature of thermal cavitation was obtained.

The Influence of Adapter and Contraction Section on the Flow of Concentric Canister Launcher

ZHANG Ying-qi, LE Gui-gao, MA Da-wei, FENG Guo-tong

2018, 38(6): 557-564. doi:10.15918/j.tbit1001-0645.2018.06.002

Abstract(1001) PDF(433)

Abstract:
This paper aims at evaluating the thermodynamic environment of concentric canister launcher system. Based on the 3D Reynolds average conservation Navier-Stokes equations, component transport model and dynamic mesh update method, numerical calculation model of concentric canister launcher system was established. The validity of the numerical simulation model was verified by launching tests with 1:1 prototype launcher. The influence of adapter (also called lateral damping support system) and contraction section on the thermal environment of gas flow field was analyzed by simulating the 3D unsteady flow field of concentric canister launcher of different structures. The numerical results and experimental results showed the thermal shock effect and variation law of gas flow on guiding cone, launching barrel, missile, etc. The results indicate that the adapter and the contraction section have a great influence on the thermodynamic environment of missile launching. The research results provide a reliable theoretical basis for further study of thermodynamic environmental influence on dynamic response with concentric canister launchers.

Investigation on Crater Depth of Projectile Penetrating into Reinforced Concrete Target

ZHANG Shuang, WU Hai-jun, HUANG Feng-lei

2018, 38(6): 565-571. doi:10.15918/j.tbit1001-0645.2018.06.003

Abstract(1270) PDF(486)

Abstract:
The investigation on crater depth can improve the calculation precision of penetration depth and overload. Firstly, a new crater depth model which considered projectile weight and initial velocity was established through the summary and comparison of existing crater depth models and the regression analysis of experimental data. Then, the crater depth calculation method of projectile penetrating into reinforced concrete target was proposed on this basis. Finally, combined with the dynamic spherical cavity expansion theory in reinforced concrete established by the authors earlier, the new crater model was used and analyzed based on the experimental data from references. This model considers projectile weight, initial velocity and laying depth of the first layer of reinforced mesh, and it can be used to predict the crater depths of projectiles with different weights and different initial velocities penetrating into reinforced concrete targets. Especially, this model provides a basis for predicting crater depth of large mass projectile and reinforced concrete.

Investigation of New Type Annular Shaped Charge Formation Mechanism

XU Wen-long, WANG Cheng, XU Bin

2018, 38(6): 572-578. doi:10.15918/j.tbit1001-0645.2018.06.004

Abstract(1098) PDF(762)

Abstract:
A new structure of annular shaped charge jet was proposed to solve the deficiency of existing annular shaped charge, such as poor stability, lower velocity, etc. Based on the orthogonal optimization method, the influence of liner thickness, radius of curvature of liner, the cone angle of the focusing device, the diameter of the nozzle and the thickness of the shell on axial and radial velocity of jet tip was measured by Autodyn software. A new type of annular shaped jet with high axial velocity and low radial deflection speed was optimized and verified. The experimental results are in good agreement with the numerical simulation results. The numerical simulation and experimental results show that the new annular shaped charge structure proposed in this paper can form an annular hole on steel target, with hole diameter of 107 mm, and depth of 28 mm.

High Bench Cast-Blasting Effects Influenced by Delay Time

LI Xiang-long, LUO Hao-hao, HU Hui, ZHANG Song-tao, LI Ke-gang

2018, 38(6): 579-584. doi:10.15918/j.tbit1001-0645.2018.06.005

Abstract(821) PDF(519)

Abstract:
In order to study the reasonable delay time of high stage throwing blasting, a similar material simulation experiment was conducted, the finite element software ANSYS was used to simulate the throwing blasting model with different millisecond delays. The test and calculation results show that:from the perspective of increasing maximum throwing distance and reducing boulder yield, when the interval between milliseconds is less than or equal to 2 ms, a portion of the energy in the rear row of holes is used to work on the broken pieces of the first row of holes, the pitch of the first row of holes is increased, and boulder yield of the first row of holes is also reduced; from the point of stressing superposition affection which is beneficial to the improvement of the three directions ofx,yandz, the delay time of the second successive holes should be 1.27~2.04 ms. Since the geometric similarity ratio of the model size to the prototype size is set at 1:50,it is recommended that the extension time of the row of high-level throwing blasting in mines be 63.5~102.0 ms.

Modeling of Two Jet Gas Devices and Its Firing Efficiency Comparison

SONG Jie, QIU Ming, LIAO Zhen-qiang, WANG Tao

2018, 38(6): 585-592,605. doi:10.15918/j.tbit1001-0645.2018.06.006

Abstract(817) PDF(771)

Abstract:
A recoilless device using double nozzle was presented to reduce the loss of bullets' velocity and improve the recoil efficiency. Based on kinetic theory of supersonic gases, considering the after-effect process, a gas dynamic model of large-caliber weapons was established for the interior ballistic. The mathematical model of gas dynamics was proved to be effective by experimental tests. The properties of system parameters of two recoilless devices including muzzle velocity, anti-recoil efficiency, motion characteristics of automation and recoil force were compared and discussed. The results show that reducing recoil efficiency of large-caliber weapons using the recoilless device with double chamber is remarkably improved and recoil force is reduced effectively.

Cooperative Guidance and Control Law Based on Decentralized Communication Topology

WANG Xiao-fang, ZHANG Yi-wei, TIAN Zhen

2018, 38(6): 593-599. doi:10.15918/j.tbit1001-0645.2018.06.007

Abstract(997) PDF(509)

Abstract:
A cooperative guidance and control law was proposed concerning multiple slide-to-turn missiles with decentralized communication attacking the target based on the leader-follower mode. The leader was supposed to attack the target according to proportional navigation guidance law. The reasonable communication topology was set and the leader was set to be the root of the topology, and then the range-to-go of each missile was regarded as a cooperative variable, the consensus cooperative strategy was discussed under the fixed communication topology and changing communication topology, which made the range-to-go of followers consensus with that of the leader. Then the expected range-to-go of followers was obtained from the consensus cooperative strategy. Based on feedback linearization theory and the constraint of missile's gimbal angle, the command of velocity lead angle of missile was deduced to make the follower's actual range-to-go track the expected range-to-go. Considering missile's guidance and control together, the integrated guidance and control model of follower in horizontal plane was established, a robust controller was designed based on the sliding mode dynamic surface theory to track the command of velocity lead angle with high precision. Simulation results proved the validity of the cooperative guidance and control law.

Electromechanical Coupling Model and Experimental Analysis of Double Clamped Trapezoidal Beam Piezoelectric Energy Harvester

ZHANG Guang-yi, JIN Lei, GAO Shi-qiao, LIU Hai-peng, NIU Shao-hua

2018, 38(6): 600-605. doi:10.15918/j.tbit1001-0645.2018.06.008

Abstract(1123) PDF(452)

Abstract:
To deal with the low-frequency vibration energy in daily environment, the harvester's electromechanical coupling model was made based on the piezoelectric structure with double clamped trapezoidal beam piezoelectric structure, and corresponding experiments were conducted to verify the model. The research shows that the results of the theoretical model are in good agreement with the results of the experiments. When the trapezoidal beam structure is in a state of resonance (96.85 Hz) and the acceleration is 2 m/s², open circuit output voltage is 44.43 V and the maximum output power is 6.16 mW. In addition, in order to compare double clamped trapezoidal structure and rectangular beam structure, experimental results shows that the double clamped trapezoidal beam piezoelectric structure has the function of reducing resonance frequency; compared with the rectangular structure, its output open circuit voltage increases by 22.7%, the output optimal load power increases by 33.0%.

Prescribed Performance Control for Two-Axis Seeker Servo System

LEI Hu-min, WANG Ye-xing, BU Xiang-wei, YE Ji-kun

2018, 38(6): 606-611. doi:10.15918/j.tbit1001-0645.2018.06.009

Abstract(1136) PDF(463)

Abstract:
Aiming at improving the dynamic performance and robustness of two-axis seeker servo system, this paper proposed a method without relying on initial errors. By designing a new performance function, the limit of initial errors has to be known was canceled, so the controller design was simplified. Aiming at the problem of composite disturbance and parameters perturbation as well as the requirement of high tracking precision, the prescribed performance control applied in this paper limits the angle and angular velocity tracking error within the predefined function bound, thus, the steady and dynamic performance of the system were guaranteed. Stabilized analysis based on Lyapunov theorem was carried out, the stability was guaranteed. Simulation shows that the method in this paper possesses strong robustness and high precision, the tracking ability of the system is promoted. Furthermore, the structure of the algorithm is simple, the application potential is broadness.

Modeling and Dynamics Analysis of Work-Class ROV Propeller

LI Xin-fei, YUAN Li-hao, WANG Hong-wei

2018, 38(6): 612-618. doi:10.15918/j.tbit1001-0645.2018.06.010

Abstract(1315) PDF(529)

Abstract:
In order to study dynamic response characteristic of hydraulic propeller control system for a work-class ROV(remotely operated vehicle),a dynamic system model for hydraulic thruster controlled by a servo valve was constructed with respect to propeller dynamic load characteristics. A solution method for motor flow,motor pressure,motor speed,propeller torque and thruster was presented. The dynamic response characteristics of hydraulic propeller control system with different step control voltages were analyzed by numerical simulation,constructing a thrust constraint model in thrust allocation and obtaining the nonlinear function relationship between the control voltage and the expected thrust. Compared with tank test results of hydraulic propeller,the simulation results show the model is accurate and reliable for the analysis of motion control,thrust allocation and hydraulic propeller control of underwater vehicles and dynamic positioning ships.

Scale-Invariant Local Feature Extraction Method for Non-Rigid 3D Model

ZENG Hui, LIU Wen-li, YU Hai-peng, LIU Ji-wei

2018, 38(6): 619-624. doi:10.15918/j.tbit1001-0645.2018.06.011

Abstract(851) PDF(406)

Abstract:
In this paper,a novel scale-invariant local feature extraction method was presented for non-rigid 3D model,called LMP-HKS (local multilevel pattern based heat kernel signatures). Firstly,a coding method was designed based on the local multilevel pattern to describe 1D (one dimension) signal suitably. Then the feature histogram was computed with local multilevel pattern to describe the logarithm difference of the heat kernel signatures. Analyses results show that,the proposed method can not only retain the excellent characteristics of HKS feature,such as isometric invariance,completeness and stability et al,but also keep the local feature scale invariant. Compared with SI-HKS feature that is also scale invariant,the LMP-HKS feature shows better descriptive ability for local shape structure of the 3D non-rigid model. The effectiveness of the proposed local feature has been validated by extensive non-rigid 3D model retrieval experiments.

An Improved Adaptive Extended Kalman Filtering Algorithm of SINS/GPS Tightly-Coupled Integrated Navigation System

MENG Xiu-yun, WANG Yu-yan

2018, 38(6): 625-630,636. doi:10.15918/j.tbit1001-0645.2018.06.012

Abstract(1190) PDF(575)

Abstract:
To deal with the problem that process noise covariance matrix and measurement noise covariance matrix in adaptive extended Kalman filtering algorithm cannot be estimated at the same time, a new kind of improved adaptive extended Kalman filtering algorithm was proposed. Based on residual sequence, this algorithm mainly improved the adaptive estimator of filtering algorithm, which could estimate process noise at real-time after improvement. Based on this algorithm, a new filter was designed to be applied to SINS/GPS tightly-coupled integrated navigation system, which could automatically adjust covariance matrix as noise varied in the system. Finally, extended Kalman filtering (EKF) and the improved adaptive extended Kalman filtering (AEKF) were applied respectively to simulate SINS/GPS tightly-coupled models. Tests show that the improved adaptive extended Kalman filtering has fewer positioning errors and velocity errors, and better stability of filtering than EKF.

Study on Ensemble Soft Sensing Method Based on ICA Variables Grouping

YANG Kai, SUN Yu-mei, WANG Li, DU Ni, CHEN Xiang-guang

2018, 38(6): 631-636. doi:10.15918/j.tbit1001-0645.2018.06.013

Abstract(910) PDF(450)

Abstract:
A novel soft sensing method was proposed based on independent component analysis (ICA) fortified with variables grouping and ensemble learning method.First,the import process variables were grouped using ICA algorithm,developing multiple variable-group subspaces.Then,the coupling relation among variables and variable groups was reduced by re-sampling the data samples in the variable-subspaces.And prediction sub-models were constructed based on kernel partial least square method (KPLS).Finally,Bayesian inference method was used to integrate the outputs from sub-models,and to get the predicting results.The superiority of the proposed method was demonstrated with comparative studies of multiple soft sensors using the industrial rubber mixing process data.

Optimal Polynomial Guidance Law with Impact Angle Constraint

ZHAO Yao, YANG Shu-bo, MO Jin-he, HAN Ying-hong, LIU Xiang-dong

2018, 38(6): 637-640,646. doi:10.15918/j.tbit1001-0645.2018.06.014

Abstract(951) PDF(427)

Abstract:
To deal with the guidance problem of intercepting ground fixed target, a two-dimensional polynomial guidance law was proposed based on a nonlinear engagement dynamics model for the missile. The main feature of this guidance law is that it not only accurately satisfies the terminal impact angle constraint, but also minimizes the specific cost function. Moreover, the closed loop system states can be analytically derived, which realize quantitative analysis for the system states. The effectiveness of the proposed guidance law was verified by numerical simulations.

Welding Joints Defects Segmentation Based on Improved Active Contour Models

LI Ye, WU Zhi-sheng, LIU Cui-rong

2018, 38(6): 641-646. doi:10.15918/j.tbit1001-0645.2018.06.015

Abstract(670) PDF(462)

Abstract:
A new improved segmentation method based on active contour models was proposed to solve the problems, like uneven illumination, low-rise contrast, blurry defect edge and other drawbacks in the X-ray welding image. An average shift histogram was introduced into the traditional active contour models to estimate the nonparametric probability, to make the model be driven by both gradient forces and statistical pressure, so as to solve the problems in the initialization and accurate segmentation about welding joints defects. The experiment results show that, the proposed method can extract welding joints defects from the X-ray welding joints image accurately, and improve segmentation accuracy.

Mechanical Model and Damage Mechanism of Filament Wound Composite Sandwich Cylinder Under Axial Compression Loading

ZHOU Xiao-song, MEI Zhi-yuan, ZHANG Yan-bing

2018, 38(6): 647-654. doi:10.15918/j.tbit1001-0645.2018.06.016

Abstract(983) PDF(596)

Abstract:
In order to reveal the energy absorption mechanism of the filament wound composite sandwich cylinder in the view of structural mechanics,a mechanical model of the structure was established under axial compression loading. Considering the force equilibrium and displacement compatibility between the surface and core,the relationship between the lateral restraint stress and core compressive deformation was put forward. The influence of hoop restraint stress on the damage mechanism was analyzed and the influence rules of parametric design between the surface and core was also conducted. The results of experimental studies and failure mode analysis show that, the mechanical model can effectively reveal the energy absorption mechanism in the view of structural mechanics and guide the parametric design of the structure.

Preparation Process and Mechanical Properties of Different Resin Matrix Composites Reinforced by Woven Basalt Fiber

YANG Zhi-ming, LIU Jin-xu, FENG Xin-ya, LI Shu-kui, WANG Xin-lei

2018, 38(6): 655-660. doi:10.15918/j.tbit1001-0645.2018.06.017

Abstract(1028) PDF(587)

Abstract:
Five kinds of different resin matrix composites reinforced with same woven basalt fiber content were successfully prepared by three different preparation techniques.The five kinds of resin matrix include epoxy resin,vinyl ester,nylon 6,polycarbonate and ABS resin.The obtained woven basalt fiber reinforced resin matrix composites are uniform and dense,and woven basalt fiber layers have same distribution.Quasi-static tensile and three point bending mechanical properties were studied,and the influences of resin types on mechanical properties were discussed.Meanwhile,the failure mechanisms of woven basalt fiber reinforced resin matrix composites under quasi-static tensile and three point bending loading conditions were analyzed,and the factors that influence mechanical properties were revealed.

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