Table of Content

10 July 2018, Volume 29 Issue 13

Previous Issue    Next Issue

Modeling and Analysis on Starting Characteristics of CPMGs

GE Yanjun;YUAN Zhi;ZHAO Peng;ZHOU Kaikai;FANG Fei

2018, 29(13):  1513-1518,1523. 

Asbtract ( )   PDF (4980KB) ( )  

References | Related Articles | Metrics

The starting characteristics model of CPMGs were put forward based on rotor dynamics. Influences of gearing ratio， starting position and output speed of driven rotor on the starting characteristics of CPMGs were analyzed. By the transient finite element method， three CPMGs were established with same structural parameters and different gearing ratios， the starting characteristics were analyzed in different gearing ratios. When the gearing ratio containing as 0.75， starting characteristics are the best. Based on the theorem of moment of momentum， the influences of the starting positions with the driven rotor on the starting characteristics were given， and the optimum starting position was obtained when the output torque was equal to the load torque. By calculating alternating periods of output torques， the relationship between the output speeds and alternating periods was obtain， when the driven rotor output speed is larger， the alternating period of output torques is larger， the CPMGs are easy to start.

A Method Building Complete Reduced Space for Structural Static Responses

ZHANG Zheng;LI Jian;ZENG Qin

2018, 29(13):  1519-1523. 

Asbtract ( )   PDF (4301KB) ( )  

References | Related Articles | Metrics

The completeness analysis and building were conducted for the reduced basis space of structural static reduced responses with variable parameters. The solution precisions of structural static reduced responses were often influenced by the reduced spaces. An optimization model for selecting response basis was formed with applications of the vector subspace angle， which was used for quantifing the relationship between the response basis vector and subspace in the reduced basis. Subsequently， an optimization algorithm was utilized to choose the optimum basis vector in the response sets associated with the parameter domains step by step， in which the reduced basis space then tended towards more completeness and the obtained reduced responses of structure became also more accurate. The examples herein demonstrate the feasibility and effectiveness.

An Online Complex Tool Path Smooth Compression Algorithm Based on Interpolation Curve Fitting Method

TAO Hao;HE Gaiyun;WANG Taiyong;DONG Jiajia;ZHANG Yongbin

2018, 29(13):  1524-1530,1539. 

Asbtract ( )   PDF (6396KB) ( )  

References | Related Articles | Metrics

An online complex tool path smooth compression algorithm was proposed based on interpolation curve fitting method. The original data points were preprocessed off-line according to the selected strategy of the dominant points， and then followed by an online interpolation curve fitting of the dominant points and non-dominant points-- error detection， and a B-spline curve was generated to meet the accuracy requirements. The dominant points were selected according to the curvature threshold， the curvature maximum value， the curve inflection point and the error maximum points after Bezier curve fitting for the dominant points. A length equalization strategy was proposed to extract the length mutation points as the new dominant points to ensure the accuracy of the local Bezier curves fitting with C2 continuity. After B-spline curve interpolation fitting of the dominant points， a contour error following method was applied to detect the errors of non-dominant points， which was more faster and effective than Newton iteration method. The simulation results show that the proposed algorithm herein may smooth and compress the complex tool paths， and the accuracy of the error detection method is satisfied.

Dynamic Topology Optimization of Free Damping Structures Based on Modified Optimality Criterion Method

HE Honglin;XIA Ziqiang;YUAN Weidong

2018, 29(13):  1531-1539. 

Asbtract ( )   PDF (7457KB) ( )  

References | Related Articles | Metrics

Aimed to solve the problems of topology optimization of free damping structures, the finite element method of modal strain energy was adopted, the relative density of the units was designed as the topological variables and the changes of material amount and frequencies were taken as the constraint conditions. A topology optimization model with the weighted sum of multi-modal loss factors was built as objective function. The expression of objective function to the design variable sensitivity was deduced. Considering that when the conventional criterion method was used for structural dynamic optimization,the objective function was non-convexity and the negative design variable appeared during its iteration, so that the optimization results did not converge or fell into local optimization. On the basis of the general optimal criteria, the iteration improvement was processed in the sense of mathematics. This method solved the problems of the negative design variables or iterative divergence, ensured all the topological variables to be involved in the processes of iteration. The free damping plates were simulated by ANSYS programming as well as the morphological step of structure was controlled by the MAC factor. The results show: when the damping material volumes are controlled to 60% pre-optimized volume by improved algorithm, after several iterations, the objective functions and topological configurations of each order tend to be stable, the cell intermediate density region is relatively small, and the free damping structures achieve an effective damping.

Dynamics Model and Performance of Steel Cable Structures Based on ANCF

QIAN Yanyi1;WANG Hui2;YU Haidong1

2018, 29(13):  1540-1546. 

Asbtract ( )   PDF (5439KB) ( )  

References | Related Articles | Metrics

A steel cable element model was established based on ANCF that was suitable for the cross-section deformation and rotation problems of cables. The deformations might be computed by the higher-order shape function. The deformations and dynamic hysteresis of cables were calculated considering the gravity. The rationality of the model was verified by the analytical solutions of quasi-static experiments and dynamic loads. The quasi-static deformations and dynamic performance of cables were numerically analyzed by MATLAB with various load cases， material properties and geometrical parameters. The results show that the cable stiffness depends mainly on the diameter. The initial tension and cable length have limit effects on the cable structure deformations. The dynamic hysteresis of steel cable mainly depends on the length and material properties. The cable structures with larger diameters and proper initial tensions have the higher stiffness and smaller deformation，which improves the performance in long-distance transmission task.

Research on Design of Aircraft Electric Wheels and Simulation for ETS

ZHANG Wei1，2;LI Kaiwei1;WANG Wei1;WANG Liwen2

2018, 29(13):  1547-1552. 

Asbtract ( )   PDF (4619KB) ( )  

References | Related Articles | Metrics

In order to improve taxiing effectiveness， save taxiing time and fuel consumption， a scheme of converting main landing wheel of an aircraft into electric wheel was proposed based on the conception of an aircraft ETS. The operating principles and compositions of the ETS were introduced. The transmission solution of ETS was formulated and partly remodeled based on the original model of main landing gear. Driving structures and installation ways of the electric wheels were redesigned. The space vector control technology of PMSM was applied to establish the simulation model for ETS by MATLAB/Simulink， the taxiing performances of system were analyzed. The simulation results show that automatic taxiing speeds of aircraft meet the requirements and the transmission solution is feasible.

Theoretical Modeling and Experimental Verification of Ball-end Milling Curved Surface Micro-units

ZHANG Wei;DU Xiaofeng;CHENG Chao;LI Pengfei

2018, 29(13):  1553-1559. 

Asbtract ( )   PDF (4797KB) ( )  

References | Related Articles | Metrics

Aiming at unique “small pits” micro-units structure of ball-end milling machined surface， and combined with the mathematical relationship among surface topography geometric parameters， the characteristic parameters and characteristic line expressions of the micro-units were solved. According to the experimental results， the characteristic parameters of the micro-units were corrected and the accuracy was verified. Furthermore， the three-dimensional simulation shape of curved surface micro-units was established. The research results show that the width relative error of the modified surface micro-units is as 1.88% and the length relative error is as 7.60%， which indicates that the theoretical model is more accurate.

Research on TRIZ & DFSS Integrated  Innovation and Integration in Problem Definition Phase and Applications

YAN Hongbo1，2;CAO Guozhong1;TAN Runhua1;YANG Zezhong2

2018, 29(13):  1560-1567. 

Asbtract ( )   PDF (6214KB) ( )  

References | Related Articles | Metrics

Aiming at the problems about current researches on integration of TRIZ and DFSS stayed at using TRIZ to solve conflicts in DFSS processes and key problems might not be identified in engineering problem solving processes， TRIZ and DFSS integration was needed to solve practical problems. The necessity and feasibility of TRIZ and DFSS integration were discussed. DMADV（define, measure, analyze, design, verity） process of DFSS was selected to conduct TRIZ tools integration， a framework was built and the core key techniques were expounded. The TRIZ and DFSS integration was focused in problem definition phases， integration routes and implementation steps were proposed， and the diesel fuel oil supply system design example was used to verify the method. The research formed a complete and executable integrating innovation method of TRIZ and DFSS， which might solve practical engineering problems for enterprises and provide guidances to realize multi-method integrating innovation.

Design and Test Study on Deep-sea Bucket Foundation Installation Equipment

LI Dewei1，2;DING Zhongjun2;REN Yugang2;SU Xiaofeng2;LI Baogang2;YANG Lei2

2018, 29(13):  1568-1573. 

Asbtract ( )   PDF (4797KB) ( )  

References | Related Articles | Metrics

Combined with the needs of exploration and development of deep-sea oil and gas fields in China，deep-sea bucket foundation installation equipment prototype was premised and manufactured.In the premise of ensuring the pressure，sealing，the size and the mass of the prototype was required to be minimized，and the function of the prototype was ensured to be proper.By using the similar geological sand materials of the South China Sea，15 MPa high pressure test of prototype was finished to ensure that the equipment might work in the deep sea environment.Experimental data was recorded and summarized as follow：penetration function of the bucket foundation is realized with the displacement of 11.23 mm and the displacement accuracy is as 1 mm.The maximum inclination of X axis is as -1.24° and the maximun inclination of Y asis is as 0.91° and the inclination accuracy is as 0.1°.The experimental processes are stable and meet the technical requierments.

Aerodynamic Optimal Design of Low Noise Wind Turbine Blades

WANG Quan1;HONG Xing1;YANG Jianzhong2;WANG Jun1;SUN Jinfeng1;QIN Zhengzheng1

2018, 29(13):  1574-1579,1587. 

Asbtract ( )   PDF (5215KB) ( )  

References | Related Articles | Metrics

In order to study the noise problems of MW-size wind turbine blades， the objective function with the maximum power coefficient to noise was proposed based on BEM theory and noise calculation model under the giving work conditions. A mathematical optimal model was established， where the chords and twist angles were used as the design variables which might influence the noise performances of wind turbine blades. The actual design of a 2.3MW wind turbine blades was optimized. The optimal noise results were compared with the noise experimental data. The results show that the predicted noise values are agreed with experimental ones in the main frequency fields. Compared to the actual blades， the new blades have lower noise which the noise pressure level is reduced by 7.1%， and the power coefficients are also improved. The feasibility for the novel design method was verified.

Tool Path Generation and Simulation for Diamond Turning of Toric Surfaces Using Three Bending Moment Method

YANG Jun;KANG Min

2018, 29(13):  1580-1587. 

Asbtract ( )   PDF (5177KB) ( )  

References | Related Articles | Metrics

In order to solve the difficult machining problems， the diamond turning of toric surfaces was discussed. In the tool path generating processes， an integrated discretization method was proposed for the discretization of cutting contact points. Besides， the distances in Z direction of adjacent cutting contact points were set up to reduce the tool movements resulting in the decrease of discretization errors. For the interpolation of cutting location points， the three bending moment method was proposed to realize the continuous of second order derivative. The simulation results indicate that the integrated discretization method may reduce discretization errors and the interpolation errors were decreased from 0.35 μm to 0.001 2 μm. The experimental results show that the tool path generation is practicable and the surface quality of workpiece will be improved.

Fatigue Analysis of a Medium Truck Cab Based on Virtual Iteration and Finite Element Theory

LIU Jun1;LIU Yajun1;ZHANG Shaohui1;YANG Jiansen2;DONG Qiangqiang2

2018, 29(13):  1588-1595. 

Asbtract ( )   PDF (6590KB) ( )  

References | Related Articles | Metrics

Taking the cab of a medium truck as the research object， the acceleration response signals of the cab mounting positions and the corresponding positions on the frame were obtained through the typical reinforced road tests. The center of mass， moment of inertia of the cab and stiffness and damping of the bushing were measured based on the K&C test bench and the MTS test rig. The rigid-flexible coupling multi-body dynamics model of the cab and frame was established in ADAMS software. The load spectrums of the cab suspension and flipping mechanisms were calculated by the method of virtual iteration in Femfat.lab software. Finally， fatigue analysis was carried out in the fatigue simulation software nCode with the Miner linear-cumulation fatigue damage theory. The results of fatigue simulation were validated by bench tests and the fatigue life of cab front panel was satisfied by redesign of the structural parameters.

Thermal Characteristics Analysis and Structural Optimization of Horizontal HMC500 Spindle Systems

WU Yongwei;WU Zaixin;BAO Zhenwei

2018, 29(13):  1596-1602. 

Asbtract ( )   PDF (5055KB) ( )  

References | Related Articles | Metrics

Taking the unique structure of the HMC500 spindle systems as the research object， the temperature field model of the spindle systems was established. It is found that the thermal deformations of the spindle systems have a good correspondence with the temperatures. Spindle deformation increases are caused by spindle heat increases. The spindle bearing friction heats are an important reason for the heat generated by the spindle systems. The experimental results show that the maximum temperature rise of the spindle systems is located in the inner rings of the front bearings. The thermal deformations of the spindle systems were further calculated， and the optimal design of the cooling surface of the spindle boxex could reduce the temperature rise of the spindle systems effectively， so that the thermal deformations of the spindle systems could be minimized， so that the key part is less than 10 μm， which may meet the design claims of the machine. On the spindle box system of the optimized arrangement of temperature sensors and displacement sensors， the real-time measurements were carried out under the speed of 8000 r/min. The experimental results were compared with the simulation ones of ANSYS to verify the feasibility and reliability of the optimized structure.

Experimental Study on Moving Regulation of Dusts in Thermal Spraying Workshops with Different Ventilation Patterns

LI Xinyu;ZHAN Shaoyi;BAO Hong

2018, 29(13):  1603-1609,1637. 

Asbtract ( )   PDF (6757KB) ( )  

References | Related Articles | Metrics

In order to obtain the control measures of ultrafine particles in the thermal spraying processes， the similar model of thermal spraying workshops was established by combining the similarity principle and the gas-solid two-phase flow theory based on the actual thermal spraying workshops. The diffusion regulations of ultrafine particles were studied experimentally under different ventilation conditions. The results show that mechanical ventilation has a significant effect on reducing the concentration of ultrafine particles in thermal spraying workshops. Both of the concentration of ultrafine particles and the time of dust removed entirely decrease with the increase of the ventilation flow per unit time in the workshops. The ventilation combing the bottoms and the sides is suitable to achieve the removal and sedimentation of ultrafine particles compared with the strong ventilation over a single side under the same ventilation rate.

Composite Repair Method of Crane Metal Constructions

KONG Puping;LIU Zhiping;ZHOU Kai;MAO Yanfei

2018, 29(13):  1610-1614. 

Asbtract ( )   PDF (3887KB) ( )  

References | Related Articles | Metrics

Crane metal constructions under long-term alternating loads were easy to produce fatigue cracks， a combination of CFRP and stop-hole was studied to rapair the cracks herein. Firstly， the finite element models of stop-hole， CFRP and composite repair were established， and the stress-strain states and stress concentration factors were analyzed. Then， the finite element model of composite repair with the stop-hole missing crack tips was built to study the effects of CFRP reinforcement on the repair of stop-hole. Finally， the effectiveness of composite repair for damaged members was studied by static tensile strength tests， the feasibility of this technology was verified through comparing the testing and simulation results. The results show that the composite repair method may eliminate the singularity of the crack tips， reduce the nominal stresses， improve the bearing capacities of the specimens， and make up for the weld cracks inadequacy of drilling stop holes， which provides an reference for engineering maintenances.

Fatigue Damage Evaluation of Remanufacturing Cores Using Feature Fusion of Magnetic Memory and Surface Texture

LIU Tao1;BAO Hong2;ZHU Darong1;WANG Fangbin1;LEI Jingfa1

2018, 29(13):  1615-1621. 

Asbtract ( )   PDF (6111KB) ( )  

References | Related Articles | Metrics

In order to improve the accuracy and effectiveness of the damage evaluation for remanufacturing， a method to assess the fatigue damage of remanufacturing cores was proposed using feature fusion of magnetic memory and surface texture. The sample entropy parameters from magnetic signals and their gradients， and energy， entropy， contrast， and correlation parameters from surface texture were extracted by feature modeling of magnetic memory and surface texture. Meanwhile， the sequential variation regularities of each parameters were analyzed. The feature fusion models were established from the data layer and the index layer respectively. The parameters of magnetic memory and surface texture features were defined as non-linear mapping inputs in the data layer， and their mapping relationships with damage were obtained. Later， in the index layer， the information fusion between magnetic and surface texture eigenvalues was carried out by Dempster-Shafer （D-S） evidence theory. The Bayes approximation was used to obtain the belief function values of each evidence， then， according to the function value， the damage states were evaluated. Finally， fatigue test samples were selected to illustrate the capability of the proposed method.

Comprehensive Assessment of Surface Integrity in Two Dimensional Ultrasonic Rolling 7050 Aluminum Alloys

ZHENG Jianxin;REN Yuanchao

2018, 29(13):  1622-1626. 

Asbtract ( )   PDF (4222KB) ( )  

References | Related Articles | Metrics

The orthogonal tests of two dimensional ultrasonic rolling 7050 aluminum alloys were carried out. The surface roughness， surface hardness and residual stress were selected as the evaluation index of surface integrity. Gray correlation analysis method was used to evaluate the surface integrity. To obtain the optimal process parameters and corresponding evaluation index values， the prediction models for the evaluation index and the grey relational degree were constructed using multiple linear regression method along with studying the effects of process parameters on the surface roughness， surface hardness and surface residual stress. The results indicate that the contribution rates of process parameters are different with different evaluation indexes. The prediction models are significant at 95% confidence level， so they may be used to predict the test results accurately. The results of surface integrity obtained from the models are better than the optimal results selected from grey relational degree. The optimal process parameters obtained by the nonlinear programming solver based on the model are as follows. When the static force is as 327 N， the speed is as 400 r/min and the feed-rate is as 0.11 mm/r， the optimal surface integrity may be obtained with the residual stress -236.98 MPa， the surface roughness Ra 0.56 μm and the microhardness 695 HL.

Microstructure and Mechanics Properties of Al-Zn-Mg-Cu Alloy by High-pressure Torsion

XUE Kemin;LIU Mei;DING Yonggen;WANG Boxiaotian;LI Ping

2018, 29(13):  1627-1631. 

Asbtract ( )   PDF (3974KB) ( )  

References | Related Articles | Metrics

HPT was used to deform Al-Zn-Mg-Cu alloys under different deformation conditions. The effects of deformation parameters on microstructure and mechanics properties of the Al-Zn-Mg-Cu alloys were studied by scanning electron microscope（SEM）， energy dispersive spectrometer（EDS）， X-ray diffraction（XRD） and hardness examination. The results show that the initial microstructure is equiaxed with inhomogeneous distribution， the coarse second phase particles（Al2Cu、MgZn2）distribute along the grain boundaries. With the temperature and the number of twist turns increasing， the coarse second phase particles distributed in Al matrix reduce obviously and the distribution is more uniform. The second phase particles are re-dissolved in Al matrix and obtain a supersaturated solid solution. After HPT deformation， the dislocation density increases significantly. Otherwise the more the number of turns and deformation temperature， the larger the increase of dislocation density. On the contrary， the microcrystalline size decreases. The microhardness of Al-Zn-Mg-Cu alloy after HPT increases significantly with the temperature and the number of twist turns increasing.