Aiming at the problems that was difficult to describe the relationship between events by the Boolean logic of conventional fault tree analysis (FTA), and the insufficient of getting reliability data in the practical application, a new polymorphic system reliability assessment method using small sample based on multiple source information fusion method and T-S fuzzy faulty tree was proposed. Based on T-S fuzzy fault tree, correlation multiple source information fusion method was applied to the confirmation of the basic event reliability. Meanwhile, in order to avoid the influence of unusable data, t-test was proposed to check the compatibility between prior information and sample information, which solved the problem that the reliability of the bottom event was difficult to be determined in the small sample system, and the prediction accuracy was improved. The proposed method was validated by using main hoisting mechanism of ladle crane. The results demonstrate that the proposed method can be applied to hoisting mechanism reliability assessment of ladle crane commendably, and the technique provides support and reference to improve the reliability of hoisting mechanism.

In order to describe the degree of the structure damage which caused by the crack in the rectangular beam, a method for measuring the crack flexibility based on the natural frequencies is presented. Firstly, the first three order natural frequencies of the rectangular beam were resolved by dynamics analysis, the natural frequency database with various crack locations and flexibilities was set up, and then the surface-fitting technique was employed to draw the natural frequency influence surfaces. Secondly, the vibration signal of the rectangular beam was tested, and the first three order natural frequencies could be obtained. Thirdly, these frequencies measured were adopted to cut the natural frequency influence surfaces, and then the first three order natural frequency influence curves were drawn. The intersection points of these frequency influence curves could indicate the crack flexibility and the corresponding crack location. The results showed that the presented method could effectively measure the crack flexibility and the corresponding crack location. Furthermore, it could be seen from the measurement process of the crack flexibility that the input parameters for drawing the natural frequency influence surface were a series of sample points of the crack locations and flexibilities. These input parameters had no relation to the type of crack, the shape of crack and the calculation formula of the crack flexibility. It can be concluded that the presented method can be used to measure the flexibility of the crack with different type and shape in the rectangular beam and can provide an important reference for the study of the dynamics analysis and damage identification of the beam with crack.

With the development of the personalized design for PDC bit, the traditional artificially exploratory method has the characteristics of low efficiency, long cycle, unstable quality, complex optimization and adjustment process, which is difficult to meet the demand of the design market of PDC bit. According to the shortcomings of traditional method and the requirements of high efficiency, high quality, easy to modify, a parameterized design platform of PDC bit was developed. From top to bottom, the frame of the design platform was divided into requirements analysis layer, designing and modeling layer, performance analysis layer and data output layer. Firstly, the whole platform structure and the operation interface based on Human-Computer Interaction were designed. Secondly, by analysis and comparing various cutter modeling methods, a completely parameter driven automatic modeling was used. Finally, after summarizing the traditional design methods and principles, a system with many modular design parts was designed. The results showed that the platform could improve the design efficiency and shorten the development cycle, reduced the labor intensity, ensured the design quality and the design results conformed with the demand of use. It has positive significance for promoting the research and service of PDC bit in China.

Aiming at the problems such as the low design efficiency of aviation blade die, serious wear and difficulty in parameters correction, based on UG/Open API, the die CAD system was developed by analysis of the blade die design process, and the parametric design of die was realized and die design efficiency was improved. Based on Archard correction theory, the influence of die design parameters on the precision forging of the blade was simulated by Deform-3D software. The influence of forging speed, the forming angle and the thickness of the bridge on the wear and life of the blade were analyzed by orthogonal test. The optimal combination parameters beneficial to extend the die life were determined and the design rules of them were optimized. It was accurate and simple to make the die design parameters be determined. Through the engineering experiment, the die wear and life were analyzed and the results were in good agreement with the simulation results. It is of great significance to optimize the design and wear analysis of air forging die.

It is of significance to study the dynamic model of the seated human body, for possibly improving the research and development of dynamics response efficiency of the applications systems of the seated human body. A 4-degree-of-freedom (4DOF) lumped-parameter model was proposed, and the model parameters were identified by utilizing a multi-object function coordinated optimization-based principle. The proposed model was also compared and analyzed with other classical 4DOF lumped-parameter models. A "human-seat-automobile" 7DOF model was further established based on the proposed model. The simulation experiment of the dynamics responses of the seated human body, when the automobile on different road conditions, was conducted, and the root mean square acceleration was used to quantitatively analyze and evaluate the dynamics responses of the seated human. The research results showed that, the non-dominated sorting genetic algorithm-Ⅱ (NSGA-Ⅱ) worked effectively for coordinately optimizing the multi objectives of the 4DOF lumped-parameter models. Further, the proposed model can describe the dynamic responses for seated human body more effectively, also can be applied to the research work on riding comfort (driving comfort) of vehicles.

High precision and broadband excitation is the main development tendency of vibroseis. Through the engineering application, there are differences in the response of vibrator baseplate at different scanning frequency, which result in the output signal of vibroseis is inconsistent in the whole frequency and restrict the development of vibroseis. Therefore, it's necessary to analyze multi-frequency response of vibrator baseplate. According to the basic theory of finite element method, the finite element model of KZ-28 vibroseis vibrator was established, the dynamics responses of vibrator baseplate at different frequency was carried out and response rule of vibrator baseplate was mastered. It was found by analysis that insufficient rigidity of vibrator baseplate was the most fundamental reason which brought about the different performance of vibrator baseplate at different frequency. This study has a positive effect for design and optimization of vibrator baseplate.

In order to improve the transport efficiency of the eccentric retractable finger type conveyor, the retractable finger type mechanism of 4FZ-2000A self-propelled straw bundling machine was studied. The transport performance and its influencing factors of the device were analyzed. It was determined that the retractable finger rotary center met the conveying requirements in the fourth quadrant, and the retractable finger was collocated based on the actual demand. On this basis, a mathematical model for the transport capacity in a single transport cycle was established, and the parameters of affecting transport capacity were determined. The structure was designed and optimized by using the virtual prototype technology which took the structural parameters of the device as design variables and the maximum transport capacity in a single transport cycle as the objective function. The results showed that when the retractable finger shaft bracket length was 54.2 mm, the length of the telescopic link was 190 mm, the angle between retractable finger shaft bracket and vertical direction was 10° and the installation height was 234 mm, the maximum transport capacity was 0.79 kg, which was 36.9% higher than that before optimization. The research will lay a foundation for further study of the dynamics peculiarity of the device, and provide the theoretical basis for the actual design and production of retractable finger type conveyors.

Automobile trim cover's plastic parts are not only required highly in appearance, but also erected with many tiny gussets and other complicated structures, and it is difficult to control the injection and moulding defects such as sink marks, buckling and deformation, makes the design of product die structure and moulding process rather tough. Based on CAD/CAE technology and through simulation and analysis in the influences of gusset thickness on moulding quality, the range of buckling and deformation of the product had been obvious influenced by the of gusset thickness, but without positive correlation. Sink marks would be obviously caused by the larger gusset thickness. When the thickness was 1 mm, the minimum value of sink marks would be 0.02 mm. The molding parameters were optimized by using the comprehensive balance method, which made the maximum warpage of product decreased by about 25%. Then by Fibonacci method, sub-sectional pressure maintaining and optimization were conducted. Through iterative calculus and standard convergence for 8 times, the ideal pressure maintaining parameters were obtained and the maximum range of deformation continued to reduce about 37%, making the rage of buckling and deformation of the final product satisfied with technical requirements. A set of optimization methods for the molding process parameters of the injection molding parts with complex reinforcing plate was presented. The production practice proves that the method is simple and practical, which not only solves the problem of the shrinkage marks and unmanageable warping deformation, but also reduces development cycle and costs. In addition, it provides a reference for similar product.

In order to realize the accurate prediction of the twist springback, the process parameters must be controlled efficiently in the stamping of high strength steel sheet. The parameters of mixed hardening model based on Voce nonlinear isotropic hardening model and Chaboche nonlinear kinematic hardening model were inverted by using the response surface methodology and genetic algorithm combined with the experimental data. An evaluation index for the twist springback was proposed, which was based on the angle between two lines in different planes. The experiment of twist springback for TRIP780 high strength steel was carried out by the hydraulic press, and the twist springback angle was measured by the three-coordinate measuring instrument. The response surface model of springback angle was established based on the finite element model of the double C rail, and the parameters of mixed hardening model were determined by using the approximation of the predicted value and measured springback angle. The related factors were analyzed by the extreme difference analysis method based on the validated finite element model of the double C rail, and the key factors affecting the twist springback were determined. The results showed that the factors which had great influences on the twist springback were the friction coefficient μ, the holder force F_N, and the die fillet radius R₁ and R₂, so it provides a theoretical basis for the effective control of the twist springback.

Owning to the unique viscoelastic properties, the elastic hysteresis effect of polymer materials is much greater than that of other materials in the rolling friction. In order to explore the influence rule of elastic hysteresis effect on rolling friction force of polymer materials, a new inclined plane method using electromagnetic loading was adopted to evaluate the rolling friction force between engineering polymer like PTFE, PMMA, PEUR and hardened 45^# steel. In addition, the creep and relaxation behaviors of PTFE, PMMA and PEUR were investigated by CETR UMT-2 equipment. Based on the standard linear solid model, the expressions of rolling friction force were derived in terms of the elastic hysteresis effect, and the experimental data and simulation results were compared and analyzed as well. The results showed that the rolling friction force decreased in order of PEUR, PTFE and PMMA with the ratio of about 1:0.51:0.28 under the same experimental conditions. The simulation results were in good agreement with the experimental data, which indicated that the elastic hysteresis effect was the main source of friction resistance in polymer rolling process. Moreover, the conclusion of this research has explored a new approach for studying the rolling friction behavior of polymer from the view of viscoelasticity.

In order to study crankshaft fatigue life of high-speed crank press with reverse sliding block, the force analysis of crank slider mechanism was carried out, the dynamics equations of the mechanism were established by D'Alembert principle, and the first derivative and second derivative of the closed loop vector equations of the mechanism were carried out, and the kinematics equations and the acceleration equations of all crank links were obtained. The kinematic equations and dynamics equations were combined by simultaneous constraint method, and all equations were assembled into a sparse matrix. Dynamic simulation model of mechanism was established by MATLAB/Simulink, the sparse matrix was embedded in the simulation model as Function modular, and the iterative solution was conducted by MATLAB/Simulink. As stamping force was considered, the variation of load with time of pressure crank journal, supporting journal and balance crank journal were calculated quickly and accurately. According to the load spectrum calculated by MATLAB/Simulink, the loads were applied on the crankshaft by Workbench, and the fatigue life analysis was carried out by stress fatigue. The results showed that the crankshaft life met design requirements, and there was no obvious damage when crankshaft experienced 10⁷ stress cycles, and the minimum fatigue safety factor was 1.09. The loads of crank journal is obtained by kinematic parameters, which can actually reflect the relationship between velocity, acceleration and inertia load,and that can provide the important theoretical basis for structural design of crank, crankshaft support structures and dynamic balancing structure and the research on bottom dead center accuracy of high-speed press. The results of fatigue life analysis are closer to reality because of the variation of load is obtained by simulation, and the results provide important reference opinions for practical application of press crankshaft.

Considering low precision and efficiency of manual operation in the alignment process between aspheric lens and semiconductor laser, a system of automatic alignment was designed based on the technology of machine vision which configured with high-performance light source of CCS and high-resolution camera of Basler, high-precision images could be obtained in real time. First, the edge of aspheric lens and the semiconductor laser was fitted into two straight lines according to the algorithms of progressive probability Hough transform and iterative weighted least squares. Then, the angle between two lines were calculated and adjusted automatically, high precision alignment between aspheric lens and semiconductor laser was achieved finally. Completing the whole process within 0.5 s at the accuracy of sub-micron level, the packaging efficiency, the accuracy of the aspheric lens and the semiconductor laser were improved greatly by system. Based on high performance configuration and precise image processing algorithm, the vision alignment system has greatly improved in the traditional packaging technology, which will greatly promote the encapsulation efficiency and accuracy of semiconductor lasers in the future.

To study the mechanical property of guide foot, the detecting system, which was based on non-destructive testing technology (NDT Tech), in which the pin sensors was installed with the same strength as the core shaft of guide foots and whose signal was transmitted online by wireless signal launcher, was designed to detect the force of guide foot under different conditions online by analyzing the force of the pin. Then the field test showed that, under the condition of oblique cutting, the loads of guide foots were at random, and the effective values of ear-plates' loads were 26.1 kN and 15.1 kN in the left guide foot and the right are 45.1 kN and 21.5 kN. By FEA, it's known that the places, where were the maximum stress of the left guide foot and the right one, which were 173.87 MPa and 187.85 MPa, were located at ear-plate of guide foot in the circumstances of maximal force. And testing and analysis results provide substantial theoretical and numerical basis for the design optimization of guide foots.

Brake-by-wire technology is a development direction of the future automotive brake technology which has aroused extensive concern of domestic and foreign car manufacturers. Since the existing automotive electromechanical brake (EMB) was lack of wear compensation device which was specified in the national standard, GB12676-2014, an innovative EMB with gap automatic adjustment function was designed. The mathematical models of drive motor, motor friction, worm and gear, ball screw and loading were established by MATLAB/Simulink. By building the EMB bench, the braking performance differences between simulation and experiment were tested and analyzed under the signal of step, triangle wave, square wave and sinusoidal wave. The braking performances of EMB with the gap automatic adjustment function or nor were also tested and analyzed. The experimental results showed that the start-current of the EMB system had a "peak" characteristic and the clamping force was sensitive, which could meet the braking requirements. According to the experimental data, the parameter relations were concluded:the clamping force was linearly related to the locked-rotor current, and the characteristics of cubic polynomial were met by the relationship between clamping force and screw displacement. The correctness of the mathematical model was verified by the simulation and experimental results. A theoretical basis for reducing the force sensor and other devices could be provided by the conclusion of parameters relational characteristics. The experimental outcome indicates that the gap automatic adjustment function of the new EMB can guarantee that the brake gap and the response time are consistent at each time, which can further improve the safety of brakes.

Since the complicated structure of domestic variable diameter stabilizer and the high manufacturing cost, a new multistage variable diameter stabilizer was designed for fine-tuning horizontal well trajectory. The diameter of stabilizer could achieve multilevel changes by changing the state of the pin in the stroke control wheel guide chute under the control of drilling fluid driving force, and its working principle was introduced in view of its structural characteristics. Based on the theory of vertical and horizontal bending method and considering the combined effect of load and bending moment, a mechanical model of the downhole drilling tool assembly with multistage variable diameter stabilizer was established, the relational expression between the drilling fluid driving force and the length of the stabilizer support block was obtained and the minimum drilling fluid driving force and the drill bit tilt angle in different extension length of the support block were calculated. The results show that the multistage variable diameter stabilizer can realize the function of increasing slope, decreasing slope and stabilizing slope, which can provide technical guidance for the structural design and optimization of multistage variable diameter stabilizers.

The middle of kinematic chain in existing 3-RPS parallel mechanisms possess a passive straight prismatic pair, lead to lower dexterity and load capacity of mechanisms. Based on the theory of Spheroidality of TRIZ, the dexterity and load capacity of mechanisms can be improved by changing shape and increasing the contact area of the pairs. Three types of 3-RPS parallel mechanisms with arc prismatic pairs were proposed, for the limb kinematic chain consisted of a revolute pair R, a prismatic pair P and a spherical joint S. The axes of drive pairs in those three types of mechanisms were collinear, parallel, intersect each other and coplanar, respectively. The screw formulations of kinematic joints under ordinary configuration were establishedby using the screw theory and the constraint force screws of moving platform were analyzed, which were employed to solve the degree of freedom, motion characteristics and dexterity of those parallel mechanisms. Results demonstrated the rotational center of moving platform was the center of arc of arc rods in the first type of mechanism,and moving platform rotating around the Z-axis with respect to the other two directions was decoupled. For the second and third type of mechanism, the rotational center was an intersection point of three straight lines, which was passed through each center of arc rod and the center of spherical joint, and this intersection point was changed with the posture of the moving platform. In addition, these mechanisms had high dexterity, and the dexterity of the first type of mechanism was higher than other two mechanisms, the dexterity of last two mechanisms were the same essentially. These mechanisms have some characteristics like symmetric and simple structure, high rigidity and large load capacity. Therefore, it can be widely used in virtual axle machine tool, flight simulator and medical equipment fields.