The expert system, one of the artificial intelligence research field, is widely used to meet the need of engineering equipment. However, the examples of satisfying the requirements of users are quite scarce due to the complexity of establishing the knowledge base and the lack of the guarantee of the quality. To solve this problem, the problems of knowledge acquisition were studied and the knowledge base building tool software based on fault tree was developed, which realized the function of fault diagnosis. According to the actual demand, the J2EE technique was used to develop a set of tool software for establishing knowledge base on B/S (browser/server) model, and the requirement analysis design of each module of knowledge base were carried out, which involved the design of model data structure and the design of business layer logical method. In addition, the diversity expression of knowledge model was discussed, and the complete fault tree was expressed in three naming ways. Finally, an example was given to illustrate the feasibility of the knowledge base building tool software. The results indicated that the expression way of fault tree was used as the core of knowledge-acquiring module to improve the quality of knowledge base. In the meanwhile, the Web form was selected to realize editing and inputting knowledge in multi-user/multi-workstation model to raise the efficiency of acquiring knowledge. Thus, this auxiliary system for knowledge acquirement has strong universality, and it can provide powerful support for domain experts and engineers to establish knowledge base.

Wooden residences are the traditional architectural culture of Miao and Dong nationality, and the personalized customization is the trend of wooden residence architecture design. In order to quickly configure the personalized customization component of wooden residence and make its model image truly meet the implicit needs of consumers, a personalized customization component configuration method was presented based on eye movement mode. Firstly, the compositions of wooden residence and people's cognition for component configuration were studied. Secondly, according to the idea of the ant colony optimization algorithm, a graphical model of wooden residence personalized customization component configuration process was established. The component areas in the personalized customization component library system of wooden residences were divided into AOI (area of interest) and AOF (area of fixation). Based on the data of the heat maps in the eye movement mode, the eye movement data visualization model was established. The gray-scale histogram of the area of fixation (AOF), the number of fixation points, the fixation time and the average fixation time were extracted from the example of railing part. Then, the probability selection for design feature in interest area of wooden residence personalized customization component system was calculated and the fitness function of the customized component was constructed to quest the optimal solution of the configuration scheme. Finally, taking the wooden residence customization project as an example, the configuration process of this method was related and analyzed. Combining with 7 level Likert scale experiment,the eye movement test results were compared and validated. The result of the T-test confirmed the feasibility of personalized customization component configuration method which could be configured efficiently on the basis of the implicit requirements of users. This method provides a new technical approach to personalized customization module configuration.

In order to improve the detection resolution and the stability of data detection, it is usually necessary to precisely control the sample flow rate in the flow system and analyze the effects of the sample flow rate and sheath fluid flow rate on the sample focusing core flow. The focusing state can be evaluated by the sample focusing core flow diameter and the relative position of the sample focusing core flow in the flow channel. First of all, according to the movement characteristics of peristaltic pump, an average flow weighing method was designed to measure the sample flow rate and compared with the measurement result of micro-flow sensor. Then, the relationship between the control voltage of the peristaltic pump and sample flow rate was linearly fitted by the least squares method. Lastly, the microscopic imaging method was used to measure and analyze the impact of the sample flow rate and sheath fluid flow rate on the diameter of the sample focusing core flow and its deviation distance from the flow channel centerline. The experimental data showed that the linear correlation coefficient of sample flow rate measured by the average flow weighing method and the micro-flow sensor was as high as 0.982 8. The correlation coefficient between the sample flow rate of the peristaltic pump and its control voltage was as high as 0.99, which showed that the linear relationship could be used to control the sample flow rate accurately. The diameter and position of sample focusing core flow were quickly and conveniently measured by the microscopic imaging method, which provided a guidance method for the regulation of the flow rate of samples and the sheath fluid in flow cytometer, and the test of the assembly accuracy of the flow device.

Disc brakes are widely applied in traffic tools and industry equipments. However, friction-induced vibration and noise sometimes may occur when the brake works, which is correlated closely with the friction and contact between the brake disc and brake pads. To date, it is still difficult to establish accurate contact behavior between brake parts due to many influence factors, which is a difficulty in the vibration and noise study of brake. Considering the dynamic characteristics that the contact stiffness can affect the system stiffness and thus change the modal frequency of the brake disc, an identification method of the normal contact stiffness between the disc and pads of the floating caliper disc brake based on modal frequency characteristics is proposed. The modal frequency characteristics of the brake disc under different brake pressures were obtained by utilizing the hammer impact method. The finite element model of the assembly of the brake disc and brake pads under constraint condition was built by using the software of ABAQUS. The dynamic normal contact stiffness between the brake disc and brake pads was identified according to the out-of-plane modal frequency of the first seven orders of the assembly model in the range of 1-10 kHz. Then, the reasons of the variation of the contact stiffness were analyzed from different aspects. Results showed that the contact stiffness increased with the brake pressure due to the decreasing of the porosity of the friction material, and increased with the modal order of the brake disc for the lower-order modal but almost kept invariant for the higher-order modal due to the variation of the contact area between the disc and pads under harmonic conditions. The proposed method can be used to establish the accurate contact relationship between the disc and pads for further investigation of the vibration and noise of the brake, thus improve the computation precision and guarantee the reliability of analysis result.

Calculating the basic event probabilities of failure trees is a heavy difficulty in FTA (failure tree analysis) of grinding wheel rack system of CNC (computer numerical control) grinder, because basic events are fuzzy and it is almost impossible to get enough reliability data by experiments with limited time and cost. In order to solve the problem, the fuzzy set theory was introduced and trapezoidal fuzzy numbers were utilized to describe the occurrence probabilities of basic event and top event in FTA. Firstly, the hierarchical structure of grinding wheel rack system of CNC grinder was analyzed, and the failure tree of grinding wheel rack system was established. Then, FFTA (fuzzy failure tree analysis) was made to calculate the trapezoidal fuzzy numbers of occurrence probability of top event by taking the spindle vibration sound of grinding wheel rack system as an example. According to the concept of critical importance in traditional FTA, the fuzzy critical importance for FFTA was firstly defined. Finally, the basic events were ranked according to the fuzzy critical importance, and the basic events with high degree of harm were determined. The results were consistent with the actual situation of the enterprise. The results indicate that this method can effectively solve the problem of confirming accuracy numerical value in FTA of CNC grinder, and provide quantitative calculating evidence to enhance mechanical system reliability for enterprise.

According to the characteristics of engineering vehicles, on the basis of engine configuration,a novel turbine pneumatic starter motor is designed. Some innovations was applied to the devices in starter drive, such as gear propulsion and the installing connection, and the gear clash was avoided, and the small volume, good strength, reliable transmission, long service lifetime and convenient exchanging of small gears were realized. The two stage impact turbine rotor was used on the powerplant mounting system and the intake port was made up of two stators and two rotors raising the gas kinetic energy utilization. The power transmission assembly was improved based on the ratchet clutch, the rolling friction and bearing supports were used to make the piston axial travel by the air through airway interface, which decreased the number of parts and friction. The planetary reducer was used on the decelerator assembly that could run on low speed, which had a good advantage of light weight, small volume, big torque and overload, little friction and simple structure. The in-situ test was made on the motor. The experiment showed that the structure was proportion to the car engine and more adaptive to the engine starting characteristics and requirement, which could be applied on the start of locomotive engine. The motor had wider source conditions, and the vehicles could be started multi-times without air admission, which made the start more reliable. The structure design provides an alternative way for engine starting, which also plays a role in promoting the domestic pneumatic starter motor.

In order to reduce the power consumption of the corn stubble returning machine, two bionic stubble cutting blades that utilize the cricket's incisor lobe as biological prototype were designed. The contour features of cricket's incisor lobe outline were extracted by using MATLAB, and the excellent characteristic of drag reduction was analyzed. The contour features of cricket's incisor lobe outline were subsequently applied to the design of the bionic blade A. Considering the processing difficulty and economic cost, a simplified quadratic featured contour was used for the design of the bionic blade B. Under the same working parameters (speed was 1 m/s, knife roller speed was420 r/min and tillage depth was 50 mm), the load conditions of the two bionic blades as well as the original blade were analyzed and compared through the ANSYS/LS DYNA simulation and the field test. The simulation results indicated that maximum cutting force of the bionic blade A and B were 881 N and 908 N, respectively, which decreased by 18.35% and 15.85% in comparison to that of the original blade (1 079 N). The field test results showed that the average torque and the coefficient of variation of A and B were 267.894 N·m, 2.31% and 275.843 N·m, 2.11%, respectively. In contrast, the average torque and the variation coefficient of original blade was 299.712 N·m and 2.33%. Additionally, the operation quality (stubble breaking depth and stubble chopping rate) of the three stubble cutting blades met the related national standards. This research results can provide a guide for the design of new blade with drag reduction.

In view of the typical defect-warpage deformation in the forming process of fused deposition modeling (FDM), taking the style of heating baseplate as the research focus, the numerical simulation results got by ANSYS were compared with the molding experimental data in order to investigate the influence of the ordinary heating baseplate and the jiugongge heating baseplate on the warpage deformation amount of the molded part. In the process of numerical simulation, the temperature field model of molded part on two kinds of heating baseplate was set up by the life and death unit technology, and then the thermal-force indirect coupling method was used to analyze the stress distribution of molded part. Finally the warpage deformation displacement cloud chart of the molded part was obtained and the warpage deformation amount of molded part on two kinds of heating baseplate was analyzed. In the molding experiment, the molded part was printed on the ordinary heating baseplate and the jiugongge heating baseplate, and the warpage deformation amounts of 4 corner points of molded part on two kinds of heating baseplate were measured. In the ANSYS numerical simulation and molding experiment, the maximum warpage deformation amount of the molded part on two kinds of heating baseplate was compared. The analysis result showed that the warpage deformation caused by the residual stress of the molded part on the Jiugongge heating baseplate reduced more compared with that on the ordinary heating baseplate, that was to say, in the actual printing process, the production parameters of the 3D printer were not needed to make any adjustments, only need to replace the ordinary heating baseplate at the work platform with the jiugongge heating baseplate, which could greatly reduce the deformation of the molded part. It is helpful to obtain high quality molding product, and has an important reference value for improving the quality of molded product.

Microchannel heat sink has the advantages of high heat transfer efficiency and reliability, and it is useful for cooling micro-scale high heat flux density electronic components. In order to meet the performance requirements and control cost, it is necessary to optimize the heat transfer capability and flow resistance of the microchannel heat sink at the same time. The thermal resistance network model used in the traditional research is relatively simple, which can not well reflect the response of thermal resistance and flow resistance to the topological changes of the microchannel cross-section shape, and the optimization object is usually the size of a given shape section. A single-layer silicon substrate microchannel heat sink thermal resistance network model was proposed by discretization method. The heat sink fins were separated into smaller ones. According to the response of microthermal resistance to the width of microdots, and the contribution of microthermal resistance to the overall thermal resistance, the overall thermal resistance of microchannel was described. Taking the output power of micro-pump as the optimized boundary condition and the pressure drop and thermal resistance as the optimization targets, the size of quadrilateral uniform cross-section silicon substrate heat sink was optimized by SQP (sequential quadratic programming) method. The optimization results were simulated and verified by CFD (computational fluid dynamics). The results showed that the shape of the cross section was rectangular when the height of fin was low, and it gradually turned into a triangle as the height of the fin increased. In the design range, when the microchannel section was trapezoidal, the fin section was triangular, the heat transfer efficiency and pressure drop were ralatively dominant. Under boundary point method and ideal point method, the optimization results of microchannel height, fin width, groove bottom width and groove top width were 500, 50, 64.5, 114.5 μm and 500, 50, 50, 100 μm, respectively. This method can adjust the evaluation function according to the design requirements, meanwhile, the calculation result has important engineering significance and provides reference for designers.

In simulation model based engineering design optimization, adopting high-fidelity and high-cost analysis model may cause unaffordable computational cost while adopting low-fidelity and low-cost analysis model may lead to optimization results with low reliability, which is difficult to meet the needs of engineering. In order to balance the contradiction between high accuracy and low cost,a sequential hierarchical Kriging model was established to fuse high/low fidelity data. In the proposed approach, many low-cost and low-fidelity sample points were used to indicate the changing trends of the high-fidelity analysis model, and a small number of high-cost and high-fidelity sample points were used to calibrate the low fidelity analysis model, so as to achieve high-fidelity prediction of the optimization objectives. To avoid the influence of hierarchical Kriging model errors on the optimization results, the hierarchical Kriging model was combined with the genetic algorithm to calculate the prediction interval of each generation of optimal solution according to 6σ criteria. The current optimal solution with a large prediction interval would be selected as a new high fidelity sample point. At the same time, sequentially updating the hierarchical Kriging model in the optimization process could improve the prediction accuracy of the hierarchical Kriging model near the optimal solution, so as to ensure the reliability of design results. The proposed approach was applied to the design optimization of a micro-aerial vehicle fuselage structure to verify its effectiveness and superiority. The grid models with different number of elements were selected as the low-fidelity analysis model and high-fidelity analysis model, respectively. Sixty low-fidelity sample points and twenty high-fidelity sample points were selected by optimal Latin hypercube design (OLHD) to construct the initial hierarchical Kriging model. The design optimization problem was solved by the proposed approach, and the solution results were compared with the results solved by the high-fidelity simulation model. The results showed that the proposed approach could effectively utilize the information of high/low fidelity data to construct hierarchical Kriging model with high accuracy and only a small amount of computational cost was required to obtain the approximate optimal solution. The proposed approach can effectively improve the design efficiency and provide a reference for similar structure design optimization problems.

To achieve the topology optimization of plane model with stability constraints, the stability problem is introduced into the traditional variable density method. The mathematical model of optimization problem was established by using the relative density of element as design variable, structural volume and instability load factor as constraints and structural flexibility as objective, and a variable density topology optimization method considering structural stability was proposed. Based on the sensitivity analysis of the flexibility, volume and instability load factor to design variables, the optimization criteria were derived according to the Lagrange multiplier method and Kuhn-Tucker condition. At the same time, the Lagrange multiplier of the criteria was solved through Taylor expansion of the constraints. The geometric stiffness matrix of the plane four-node quadrilateral element was deduced to calculate the geometry strain energy of the optimization criteria. Finally, the proposed method was verified by an example. Through the comparison with the traditional variable density method, it was illustrated that the proposed method could notably improve the stability of the optimization result. The research results have important guiding significance for the optimal design of the slender compression structure, and have certain reference value for the stability design of the structure.

Constructing the objective function through the math expression of the negative Poisson's ratio directly will make the objective function highly non-linear and the sensitivity analysis of the iterative process difficult when constructing the topology optimization model of negative Poisson's ratio structure. Firstly, the topology optimization objective function of negative Poisson's ratio microstructure with linear characteristic was constructed by the linear fitting method; Secondly, employing the strain energy-based method and the homogenization method and combining the topological optimization theory, a topology optimization design model was constructed, which could solve the negative Poisson's ratio quickly and accurately. The optimal topological configuration and the corresponding negative Poisson ratio were obtained by solving the model. According to the structure model obtained through optimization, referring to the national standard GB/T 22315-2008 the elastic modulus of metal materials and Poisson's ratio testing method, the Poisson's ratio was simulated by finite element software, and an experimental sample was processed by laser processing. Next, the Poisson's ratio was tested and compared with the Poisson's ratio obtained from the optimization model to verify the correctness of the optimized model. The method not only avoids the highly non-linear problem when using the negative Poisson's ratio expression as the optimization function, but also reduces the solving complexity, which provides a reference method for the design of negative Poisson's ratio microstructure.

In view of the problem of mathematical nonlinear regression, it is necessary to continuously improve the design model and design parameters, so that the design effect is the best. The response surface method is often used to optimize the minimum volume problem under the constraint conditions, which means that the simulation model is fitted by the function relation and the optimization direction is determined by the screening test. In order to optimize the shape of the classic 10-bar truss structure,based on the response surface, the APDL (ANSYS parametric design language) program was written and run, and the initial stress and volume of the truss were obtained. The change of node coordinates was used to reflect the change of shape. Each factor was set at three levels and encoded as -1, 0 and 1, and the center and level were adjusted by response surface method (RSM). Based on the adjusted level, the best neighborhood was found, and then the optimal solution of the volume under the allowable stress in the best neighborhood was solved by the optimization software. Finally, the determined node vertical coordinate value was returned to the APDL program to verify whether the constraint condition was satisfied. If it was satisfied, the volume was the best solution at this time. The results indicated that the iterations number was only 3 times when using the response surface method, which could quickly locate the optimal solution and reduce the previous design cost. By comparing the experimental design method in literature[9], it was found that the RSM was more efficient in optimizing the shape of the structure. In engineering applications, it is efficient to locate the design test program and find the best matching design under constraint conditions.

Drilling fluid vibrating screen is the key equipment of solid phase control system for oil drilling and it is used to remove the harmful solid particles in the drilling fluid and recover the drilling fluid,which is of great significance to conserve resources and protect the environment. With the development of petroleum industry, higher requirements are put forward for vibrating screen. Therefore, a new type of negative pressure drilling fluid vibrating screen was proposed. The difference between the negative pressure drilling fluid vibrating screen and the traditional drilling fluid vibrating screen was that the former combined vibration screening and vacuum filtration to improve the processing capacity. In order to understand the performance of negative pressure vibrating screen in detail, based on the single particle model of the traditional vibrating screen, the conveyance law of the solid particle on the negative pressure vibrating screen was discussed by the mechanical view, and the movements of solid particle on the two kinds of vibrating screens under different parameters were compared. Besides, the effect of negative pressure system on structure parameters of vibrating screen was analyzed. The results indicated that the conveyance speed of solid particle on the negative pressure vibrating screens was slower than that on the traditional vibrating screens,which was more conducive to the separation of the liquid and solid. In addition,the application of the negative pressure system had little influence on the structural parameters of the vibrating screen, so the conventional vibrating screen could be directly converted into a negative pressure vibrating screen. The research results provide a theoretical basis for the design and field application of the negative pressure vibrating screen.

In order to satisfy dynamic and differentiated control requirements of temperature control system for precision machine tools related parts in the condition of changing running performance and fluctuating ambient temperature, the design methods and control strategy of differentiated temperature control system for precision machine tools were provided. Firstly, the method of selecting and designing the key parts of the system and computational method of main parameters of temperature control capability were given. Secondly, dynamic on-time matching strategies for high and low temperature oil tank temperature control were proposed, according to the differences between the target temperature and measured temperature of high temperature oil tank and low temperature oil tank independently. Besides, design module for selection and computing of differentiated temperature control system as well as temperature control simulation module for high and low temperature oil tank, were developed based on MATLAB software. Finally, the rationality and feasibility of simulation module were verified by the experimental data, gathering the temperature data in actual situations and comparing the simulation data with the actual data. The examples illustrated that the design methods and control strategies were of reasonableness. The results of contrast showed that the overall situation and trend of the temperature under the actual condition can be reflected by control simulation module. The proposed design method and control strategy for differentiated temperature control system have certain feasibility and rationality, as well as higher engineering application values.

The steel cord will produce residual torsion stress during twisting, which will cause different degrees of rotation opposite the twisting direction after the twisting progress is finished, and it will seriously affect the performance of steel cord. In order to reduce the residual torsion stress in the process of wire twisting, the on-line monitoring and automatic elimination control system for the residual torsion of steel cord was designed. The software and hardware of the control system were reasonably configured by the SIEMENS S7-200 series PLC (programmable logic controller), and the hardware and the software design of the system were expounded in detail. The touch screen of the delta DOP series was used to realize the on-line real-time monitoring of the residual torsion value of steel cord. The whole machine has stable performance and realizes the control and elimination of the residual torsion, which meets the requirements of automatic production with high flexibility, high efficiency and high quality in the production line.

Crawler traction tape replacing device is a new type of belt replacing device for mine belt conveyors. The hydraulic system of crawler traction replacing device was designed and simulated by using Automation Studio software in order to understand its dynamic characteristics. After the simulation and the analysis of the drawing speed of the tape replacing device, the input flow curve, speed curve of the hydraulic motor and the drawing speed of the crawler chassis were obtained with displacement of 30, 35, 40, 45, 50 mL/r. Through the simulation of the entrainment speed of the tape replacing device, the time difference between the clamping and releasing of the hydraulic cylinder was explained and the reason was analyzed. The simulation of the entrainment speed of the anti-roll mechanism showed that the mechanism could clamp the tape within 0.2 s. In the industrial test, the pressure of the on-site hydraulic system was collected by PLC (programmable logic controller) and compared with the simulation pressure. Entrainment with constant pressure self-adjusting ensured that the system pressure remained stable even if the tape thickness was changed. Automatic lock cylinder pressure changed quickly to ensure safe tape replacement. The results show that the device has a fast response speed and stable performance, which provide a guarantee for the power and safety performance of the crawler traction tape replacing device.