Search

The precision of transferring paper is key factors to decide the print overprint accuracy, and vibration has an important impact on paper transferring accuracy. Empirical mode decomposition (EMD) can be used to extract the features of vibration test signal. According to the intrinsic mode function (IMF) by extracted, it is useful to analyze the dynamic characteristics of swing gripper arm on motion state. Due to the actual conditions of printing, the vibration signal of Paper-Transferring mechanism system is complex quasi periodic signals. Hilbert-Huang marginal spectrum that is based on empirical mode decomposition can solve the problem which is modals leakage by FFT calculated in frequency domain. Through the experimental research, the phase information of impact load at the moment of grippers opening or closing, which can be used for the optimization design of Paper-Transferring system and the improvement in the accuracy of swing gripper arm.

When processing in the manufacture for production of paperboard boxes, there arises amount of waste paper as material, which is subsequently sent for recycling. The paper passes through the first crushing device, which ensures small pieces so that they can be transported by pipeline to a pressing apparatus. Paper material in the molding machine is forced into the pits of suitable size due to the additional handling and transport. So both pipe as well as the molding machine may be so congested with material during the failure that the equipment requires unexpected additional cleaning. The sensor detects the level of waste material in pressing device, thereby avoiding congestion in a timely manner and prevents subsequent failure. The sensor uses the resonant frequency of the oscillating rod. The microprocessor controls and evaluates the response of the rod oscillations. Sensor performance was exposed to qualification tests when it shows ability to operate also in extreme conditions such as dirty and dusty surrounding with high humidity and temperature level. Sensor detects the vibration attenuation at the poles of the rod that is caused by touching different materials. Thus may indicate changing concentration level of a material and not just pieces of paper but for example, also sand or other suitable materials or height of fluid surface.

The complex nonlinear problem exists between the factors which influence the strength of hybrid fiber reinforced concrete. The nonlinear relationship between input variables as the factors and output variables as the strength can be obtained artificial neural network which have the feature of self-adapting, self-studying and nonlinear mapping. RBF and BP neural network models are established in MATLAB in this paper based on experimental values. Compressive strength and flexural strength of hybrid fiber reinforced concrete are predicted respectively and comparing with the measured values, predicted values are analyzed. The results show that the predicted values based on RBF tally with the experimental values, and the strength prediction ability of RBF is higher than BP neural network. The needs of engineering can be meet by this method with accurate prediction ability, a new method for the study of hybrid fiber reinforced concrete strength is provided.

As abrupt change of the shape and elastic constant in the weld area occurs to the welding joint, there will be obvious stress concentration near the weld area when being loaded. Lifting and Lowering Method and Grouping Method prevailing in the world are applied to conduct an experiment about fatigue strength of a certain welding joint in Wuhan Iron and Steel and S-N curve is drawn in this paper based on the condition of nominal stress. In addition, the influence of weld size of the welding joint on the distribution of stress is studied through the calculation of finite element numeral value and experimental test. According to the factor of stress concentration, S-N curve is modified to provide the data support for the application of the welding joint and assessment of fatigue strength.

To improve the calculation precision of deformation in prestressed concrete bridge in passenger dedicated line and accurately predict the development of shrinkage and creep in bridge, a universal applicable modified model was put forward in this paper based on ACI 209R(1992) shrinkage and creep model. In the modified model, three influence factors-slump, strength and reinforcement - are corrected. And the modified model results were compared with the experimental results. It shows that the modified model can more accurately predict the development of shrinkage and creep of high-speed railway bridge and better accord with the law of it.

In the paper there are presented experimental results concerning mechanical characteristics of friction-welded joints in comparison with electron beam welded joints, made by 20VNiMoCr120 heat-resistant steel, which are part of some elements working at high pressure and temperature. The paper represents a study which suggests non-conventional welding and heat-treatment procedures for water and steam-supply pipes, large cylindrical recipients with high values of wall thickness, boiler pipes, steam turbines which compose thermo-energetic installations, in order to prevent failure appearance. The actual level of development in all activity fields proves the fact that on top of the performance and modernism, technological products and processes must assure a high reliability. All the results and experimental researches are obtained by the first author in her PhD Thesis.

The paper is focused on the use of advanced composite materials in the real application areas of buildings exposed to extreme environmental stress. The paper describe properties of composite rebar, especially with regards to long-term resistance to chemical and corrosion attack, minimization of heat transfer or resistance in construction with reduced concrete cover. The paper also presents behavior of composite rebar and concrete samples with composite reinforcement during loading and fire tests.

This paper refers to behaviour and capacity of axially loaded columns strengthened under load using welded steel plates. This method of strengthening is fast, simple and widely used but no universal and reliable analytical solution has been presented yet. In the paper, focus is put on flexural buckling. The approach using cross-section properties of strengthened member and the modified buckling reduction factor was used to calculate the ultimate resistance. In buckling theory, the resistance of column subjected to compression load is reached when the most stressed fibres start to yield. However, some researchers allow certain amount of yielding for base material of columns strengthened under load. In the paper, the new modified buckling reduction factor based on Eurocodes is derived. Two types of column strengthening under various preload magnitudes are investigated using finite element study in ANSYS code and transient analysis type. Birth and death of elements is used to simulate strengthening welded plates. The results are compared with analytical solutions.

Steel silos are commonly constructed by welding together a large number of curved steel panels with lap joints.Where the lap runs horizontally around the silo circumference, the lap connection causes a local eccentricity in the line of vertical thrust in the shell wall. This eccentricity induces high local bending stresses, which are detrimental to the stability of the structure. This paper chooses a flat-bottom squat steel silo as the research object to analyze the stability of lap-jointed steel silo by comparing with a butt-jointed steel silo. By stressing loads calculated according to Chinese code for design of grain steel silos, considering two load cases including axial compression only and combined axial compression and internal pressure, this paper performs numerical analysises including linear buckling analysis, geometric nonlinear elastic analysis and geometrically and materially nonlinear analysis to study the effects of material nonlinearity and lap joint on stability.

Concrete mechanical properties under dynamic load such as blast and impact are very complex. Shock wave propagation law and damage effect in the concrete were studied numerically in the paper by using TNT explosive ignition and growth model, concrete dynamic damage model, and SPH method. And shock wave properties of different mass explosives in the concrete were analyzed with the similarity theory. The result shows that TNT shock wave propagation law meets the internal-blast similarity law. Peak pressure, positive pressure impulse, maximum velocity and maximum acceleration in the concrete decrease with the increase of scaled distance. And time needed for reaching peak pressure increases linearly with the increase of scaled distance. A theoretical basis of structure and protection design for constructions is achieved in the paper.

In the paper, according to crushing and attrition of material on mixer blade, the mechanical model of material on blade is established. According to nonlinear vibration and the basic theory of rotor dynamics, Mechanical model of vibration system and differential equations of motion are established. This paper has adopted the arithmetic of fourth-order Runge-Kutta, analyzing wave forms graph, chart of axis track, phase plane plot of system movement. Analysis results show that mixer system appears chaotic motion under some certain design parameters. This state of motion on mixers can better destroy cement coagulation group, increasing the number of effective collision of concrete particle, which can effectively improve the microscopic homogeneity of concrete and improve efficiency of concrete mixing.

Task of controlled ventilation in modern residential buildings is to ensure optimum quality of interior environment and fulfill hygienic and thermal technical requirements guaranteeing comfort of user. The paper discusses development and experimental verification of atypical vertical ventilation units of under pressure controlled ventilation system for residential high-rise building. Recommended concept of solution to façade detail in relation to ventilation system. Optimized alternative of air inlet openings in the bottom level of vertical pilaster with function of air distribution channel for under pressure controlled ventilation system. The paper discusses laboratory experimental verification of physical properties of optimized alternative of ventilation units of under pressure controlled ventilation system for high-rise residential building in their development cycle. Boundary conditions of physical designing of envelope structures for load of wind-driven rain and their modifications for high-rise building in the locality of Bratislava. Hydrodynamic regime of air inlet openings of controlled ventilation system – maintaining water impermeability of air inlet openings of the ventilation system under the effect of wind-driven rain – laboratory experimental research in large rain chamber, its results and necessary construction modifications of elements of ventilation units. Aerodynamic regime of natural controlled ventilation system – quantification of volume of air flow rate through ventilation units in dependence to air pressure difference - laboratory experimental research in large pressure chamber. Acoustic properties of natural controlled ventilation system – quantification of index of air impermeability of controlled ventilation system in open and closed position - laboratory experimental research in acoustic chambers. Comparison by the experiment of verified parameters of ventilation units of under pressure controlled ventilation with design parameters.

Condition monitoring (CM) and fault diagnosis of equipments has gained greater attention in recent years, due to the need to reduce the down time and enhance the life/ condition of the equipments. The rolling element bearings (REB) are the most critical components in rotary machines. Hence, bearing fault detection and diagnosis is an integral part of the preventive maintenance activity. Vibration signal analysis provides wide range of information for analysis. So in this paper, vibration signals for four conditions of a deep groove ball bearing namely Normal (N), bearing with defect on inner race (IR), bearing with defect on ball (B), and bearing with defect on outer race (OR) have been acquired from a customized bearing test rig under maximum speed and variable load conditions. Depending on the machinery operating conditions and the extent of bearing defect severity, the measured vibration signals are non-stationary in nature. Non-stationary signals are effectively analyzed by wavelet transform technique, which is a popular and widely used time-frequency technique. The focus of this paper is to select a best possible mother wavelet for applying WT on bearing vibration signals. The two selection criteria includes minimum Shannon entropycriteria(MSEC) and Maximum Energy to Shannon Entropy Ratio criteriaR(s). This helps in effective bearing CM using WT.

This research presents the potential for improved joint integrity of friction stir welding by controlling the plasticisation temperature in the weld nugget. During a typical FSW, temperature fluctuates with position along the length of the weld. Working from a basis that for all material and tool geometries, there is an Optimal Plasticisation Temperature (OPT), this paper provides a strategy for maintaining this optimal weld temperature by adjusting selected weld input parameters ensuring consistent joint quality, irrespective of component geometry or clamp configuration. This proposed methodology can also be used to determine the OPT for different FSW tool geometries and material combinations. Advanced monitoring and control strategies are essential to ensure that FSW can be made a more robust industrial process that can keep pace with the modern demand for more consistent production and reliability of welded structures. The potential lies in the possibility for an operator to now select an OPT point for a specific approved welding program and allow the welding platform to maintain the OPT via closed-loop temperature control which adjusts tool rotation and or tool traverse speed. This paper further reports on the potential of integration of a closed-loop temperature control algorithm for FSW. The system measures the temperature inside the FSW tool using thermocouple sensors (creating the feedback signal). The controller then applies a PID algorithm which in turn drives the spindle speed (and if necessary, tool traverse speed) in order to change the energy input rate to the weld for controlling plasticisation temperature.

Numerical simulations are powerful tool for analyzing and research in domain of mechanical constructions. In welded joints is very important to determine residual stresses and temperature distribution in sample, apropos, element of construction. In some cases doing the experiment is not possible, so numerical simulations can give the required results and overview of stress state, residual stresses, critical areas, displacement, temperature distribution and other data is needed for analyzing and improvement of constructions or parts of constructions. This analysis includes finite element model for the thermal and mechanical welding simulation. Welding simulation was considered as a sequential coupled thermo-mechanical analysis. The residual stress distribution and magnitude in axial direction was obtained. The paper also shows the results obtained in a simultaneously test of a butt welded thin steel sheet specimen by conventional methods and thermography. Numerical methods are also used in order to predict the crack of specimen. The obtained results confirm that it is very useful to use thermography and Finite Element Method (FEM) for early diagnostics of the complex structures in the exploitation conditions. In this paper is obtained good agreement of results between experiment and Numerical simulations.

The paper presents a case study on the original solution of a flange shaft as part of the root area of a 5 kW wind turbine blade. There were analyzed the causes that led to the shaft breakage under wind loadings in extreme weather conditions, and consequently technical solutions have been searched in order to improve the shaft design making it more reliable as mechanical strength at extreme wind loadings. The flange shaft is a welded subassembly that keeps the blades attached to the rotor hub. The first part of the paper consists in an analysis referring the loading status, the materials used for blade manufacturing, the identification of critical areas where the breaking was initiated and also the causes for which the materials assumed and specified in the technical design and manufacturing technology failed under loading at wind gusts of about 30 m/sec. Based on this preliminary analysis, the second part of the paper presents the technical solutions which were considered in reference to the materials and the improved design concept aiming to provide the right mechanical strength necessary to withstand specific wind loadings in extreme weather conditions.

In this paper, the temperature and pressure distribution in sensitive element of nozzle array structure gyroscope is analyzed. Using ANSYS-FLOTRAN CFD software, the finite element simulation is conducted by a series of procedures, such as two-dimensional model building of fluidic gyroscope, mesh, load applying and equation solving. The temperature and pressure distributions of nozzle array structure fluidic gyroscopes are calculated. The results show that the thermal wires heat temperature of the surrounding gas which place at 1.5mm from the outlet, and which produce internal temperature gradient in sensitive cavity, temperature changes symmetry of the cavity center. The pressure near the outlet is higher than any other position in the cavity, and which is 0.21109Pa. In this paper, the structure optimization of nozzle array gyroscope which provides effective theoretical basis for improving its performance.

Wind turbine blades are the major structural element and highest cost component in the wind power system. Modern wind turbine blade sizes are increasing, and the driving motivation behind this is to increase the efficiency and energy output per unit rotor area, and to reduce the cost per kilowatt hour. However due to the increase in size the material selection for wind turbine has become critical and complex. To achieve the desired materials to improve the design of wind turbine blades several factors such as high fatigue strength, less weight, less cost and potential of recycling must be focused. Basalt fiber is a relative newcomer to fiber reinforced polymers and structural composites. Basalt fiber with their excellent mechanical properties represents an interesting alternative composite material for modern wind turbine blades. Some manufacturers claim that basalt fiber has similar or better properties than S-2 glass fiber and its cheaper than carbon fiber. Basalt fiber together with carbon fiber are the most advanced and interesting area of hybrid technologies. This paper reviews extra ordinary properties of basalt fiber over other fiber reinforced composites and highlight how the basalt special properties together with carbon fiber will reduce the weight and cost of wind turbine blades while improving their performance. This paper also demonstrates why the basalt carbon hybrid composite material will be an ideal alternative for the wind turbine rotor blades.

The calculation of stress intensity factor (SIF) in fracture mechanics-based fatigue life prediction is mainly based on empirical formulas, the poor applicability of which limits the wide application of fatigue assessment based on crack propagation. This paper proposed a SIF calculation method for structures under wave loads. It was proved correct by comparing with the empirical formulas. Then, the method proposed was applied for the surface crack at weld toe of a connection between the column and brace of a semi-submersible platform. The predicted results showed that SIF ranges varied with wave loads, which were subjected to the effects of wave directions and frequencies. In addition, SIF ranges calculated by empirical formulas were very different from those of the proposed method. In order to accurately predict fatigue crack propagation life for ocean engineering structures, it is necessary to take the characters of wave loads into consideration. The proposed method in this paper may provide a reference.

Because of the relatively small number of the subtropical region building energy research, resulting in the construction of energy-saving measures in the area of building energy method is mainly imitate other regions. The building energy efficiency should be appropriate. And the crucial of the building energy efficiency in subtropical region is heat insulation processing. This paper presents the idea of a subtropical region suitable for natural ventilation insulated exterior wall structure. A new kind of suitable natural ventilation and heat insulation building structure for exterior wall in hot summer and warm winter area is proposed in this paper, which thermal properties is calculated by Maple software. And this paper demonstrates that this kind of structure is the feasibility of the structure. The result of the comparison of thermal properties of different insulating structure by using the finite difference method for unsteady heat conduction calculation presents that the insulation performance of the buildings which have the natural ventilation and heat insulation structure is better than the ones without this ventilation. In the end of paper, the authors descript the hope that this kind of structure will be further research and analysis.

The curling stresses of rigid pavement are the result of in-situ and built-in temperature gradient. A profound investigation on the reasons causing longitudinal cracking (LC) was conducted in this paper. Based on finite element method (FEM) analysis results obtained from ISLAB 2000, the wheel load stress generated by a single axle load that is applied along the transverse joints is considered to be the critical loading condition for longitudinal cracking. Nonlinear environmental stress due to the curling of Portland Cement Concrete (PCC) was analyzed using the numerical program developed in this study; the paving time within a day has a significant influence on the curling stresses at the top portion of PCC slab at the critical loading position for longitudinal cracking. Research in this paper proposed an analytical method to determine the influence of the paving condition (day time and night time) on the built-in setting gradient and its effect on the in-situ effective equivalent temperature differential.

In this paper, elastic hydrodynamic lubrication theory was introduced into bearing dynamic stiffness calculation process to take into account the impact of the oil film on the rolling stiffness. Dynamic characteristics of NC boring machine spindle system dedicated to the manufacturing of bearing retainer were studied based on finite element analysis software. The rationality of the structural design of spindle was verified in the paper. The research provided a theoretical basis for the improvement of machine performance and dynamic design of NC boring machine spindle.

An underground structure has been in a state of static equilibrium under the combined effect of gravity and the surrounding soils confining pressure before internal explosion occurred, and the blast wave can experience multiple reflections and diffractions in closed space, so the overpressure on the surface of structural members was more complex than that when explosion happened in the open space. In this paper, a finite element model of a closed underground frame structure was established by using the finite element software ANSYS/LS-DYNA. Based on the model, numerical simulation by stages was done to study the overpressure distribution on the surface of the retaining wall. This paper main analyzed the effect of the initial balance stress on the blast overpressure distribution rule and the retaining walls dynamic response.

The electromagnetic force which influenced by rail launcher armature position have been researched in this paper. As an important indicator, Inductance Gradient (IG) denotes the performance of rail launch, which can make the railgun performance to achieve optimal results by better design. A rectangular cross-sectional rail launcher model was built based on the Biot-Savart law in this paper. Furthermore, the analytical expression of inductance gradient can be obtained by this model. Finally, the electromagnetic force can be calculated. Some numerical simulations are made to test the validity and capability of the proposed model.

Based on force analysis of angular contact ball bearings, this paper proposes a generic mathematical modeling method. This paper conducts in-depth research for these aspects: all directions of the stiffness characteristics under different load conditions of angular contact ball bearings, internal contact deformation and the change of bearing parameters. This article eventually gets the variation of the bearing characteristics under different load conditions.

This paper reports the results of experimental research concerning the connection between the deck plate and the web of the longitudinal stiffeners in an orthotropic plated bridge deck on a microscopic scale. An important number of test specimens of a weld are studied with the help of a video microscope, to detect the efficiency of the root of the weld. The second part of the paper is concerned with parametric analysis of the lack of weld penetration by using accurate finite element modeling. The results demonstrate that the weld quality often required cannot always be assured, which surely has important consequence on the stresses in the weld and the fatigue resistance.

Because the failure behavior of the soil surrounding the Push-extend Multi-under-reamed Pile will be affected by the placed location of the bearing push-extend reamed, further, the bearing capacity of the Pile is affected, in the paper, through experimental study and theoretical analysis, it is qualitatively analyzed that the influence of the location of the bearing push-extend reamed for the bearing capacity of the Push-extend Multi-under-reamed Pile, the achievements of the paper will present the well theoretical basis for synthetically considering all of affecting factors in the design of the Push-extend Multi-under-reamed Pile.

This paper presents a new approach based on the method of magnetic flux leakage (MFL) for the double-sided butt weld (DSBW) of the welding equipment such as the pressure vessel in order to detect and identify the weld defect. In this approach, a new magnetization structure is adopted whose magnetization direction is perpendicular to weld line, also, a new continuous non-contact scanning method is used, what aims to solve the problems about complex leakage magnetic field (LMF) space distribution. Then, the LMF distribution laws with non-defect (ND) and laws with precrack from heat affected zone (PFHAZ) are obtained through using these methods such as theoretical analysis, numerical simulation, and experimental study. Afterwards, this paper reviews the recognition analysis of the above-mentioned two kinds of state (ND and PFHAZ) by binding the contrastive curves. The outcomes indicate that the suggested method of MFL has realized the recognition of ND and PFHAZ; The numerical simulation results and experimental results match each other well and their correlation coefficient R is 0.9729. Furthermore, the results verify the feasibility and the validity for the suggested method. This is a new way for exploration detection of the double-sided butt weld.

Concrete-filled steel tube structure is one of the important load-bearing systems of modern high-rise building.The research indicate that concrete-filled steel tube structure has a good static and seismic performance,and concrete-filled steel tubular component is always used as axial compression and compression-bending component.However,what about the mechanical behavior of this combinational structure (concrete-filled steel tubular columns with steel bone built-in)? So there is a new type of special-shaped cross-section of composite structure,that is the T-shaped concrete-filled steel tubular columns with steel bone.The research about this structure is less throughout domestic and foreign.So the axial compressive experiments of six T-shaped concrete-filled steel tubular stub columns, five with and one without steel bone, were carried out. The effects of tube confining factor, bone indicator on the axial compressive behavior of the columns are analyzed. Experimental results indicate that the ultimate strength of the T-shaped steel tubular stub columns with steel bone increases, can be increased by 71.7%.And that the setting of steel bone improves the confinement of the concrete core, delays or even avoids the local buckling of the steel tube before the stress attains the yield strength. The ductility of the columns is also greatly increased.And at last in this paper, use of static equilibrium conditions and limit yield conditions,and in reference to literature[1],the calculation equation of compression capacity of this combinational column is derived.Moreover,calculation results according to the formula in this paper are in good agreement with the experimental results. The conclusions might be used as reference to structural design and plan.

Retard-bonded prestressed concrete which has appeared in recent twenty years is a new and distinctive prestressed system. For the research on mechanical behavior and service property of retard-bonded prestressed concrete members, retard-bonded prestressed strands were made by manual work in this paper. Experimental research and theoretical analysis of three retard-bonded partially prestressed concrete T-beams were carried out under static loadings. The law of crack development and distribution both with the relationship between load and maximum crack width were studied in the paper. Test results were contrasted with experimental studies of two traditional partially prestressed concrete T-beams, and the characters and merits of retard-bonded partially prestressed concrete T-beams were obtained. It provides theoretical reference for the actual project application of the new retard-bonded prestressed concrete system.

The CTOD (Crack Tip Opening Displacement) evaluation and control for HAZ (Heat Affected Zone) toughness of welded joints are the most effective measures to the security of steel structures. This paper address the problem of the newly developed offshore structure steel API 2W 50Z with heavy thickness of 100mm. In accordance with the American Petroleum Institute standard Recommended Practice 2Z (API PR 2Z), the CTOD tests of two critical positions of HAZ in three kinds of heat inputs were carried out in low temperature (-10°C). All of these CTOD testing and assessments are finished under the witness of American Bureau of Shipping (ABS). The result shows that all of the CTOD values are greater than the required value (0.38mm) in API RP 2Z. This indicates that the newly developed offshore structure steel (API 2W 50Z) meet the requirement of the toughness. Further, the CTOD testing and assessments in several international standards about weld joints of steel plates are also compared and discussed in this paper.

The hammer crusher always works under heavy load, discontinuous and impact working condition, which is complex, especially when impact happens. The spindle is one of the most important parts of the hammer crusher, the performance of which has a great effect on the whole structure. This paper discussed the main loads acting on the spindle. After the multi-body system dynamics (MBD) models were built up in previous paper, three kinds of multi-body system simulation (MBS) analysis were conducted to gain the impact loads, then a static analysis of spindle was carried out with the loads, which verified the reliability of the design of the spindle. To evaluate the correctness of the MBS results, comparisons between simulation and theoretical impact force results were done, which proved the acceptance of the MBD models. Another theoretical analysis model for the spindle was established and employed to verify the results of FEA and reliability of the design of the spindle.

On this paper, a study of robot based remote laser welding technology for manufacturing light car body was conducted. Laser welding and industrial robotic systems were used with robot-based laser welding systems. The laser system used in this study was 1.6kW fiber laser, while the robot system was Industrial robot (payload : 130kg). The robot-based laser welding system was equipped with a laser scanner system for remote laser welding. Laser patterning on the fly needs to control some parameters to accomplish the desired shape and good quality of the welded pattern. The scan path and the mark speed as two control parameters of the laser scanner are numerically computed from pattern shape and robot motion. However, time-delay in operation of the laser scanner and the robot makes unexpected geometric error between the desired pattern and the welded pattern. The pattern sequence and the robot path is optimized to reduce total processing time. The proposed method is tested with various patterns and robot paths, and the welded patterns are validated by measuring their geometries and positions. Finally, the experimental results show that our method is suitable for laser patterning on the fly. The welding joints of steel plate and steel plate coated with zinc were butt and lapped joints. The quality testing of the laser welding was conducted by observing the shape of the beads on the plate and the cross-section of the welded parts, analyzing the results of mechanical tensile test. The remote laser welding system with laser scanner system is used to increase the processing speed and to improve the efficiency of processes. This paper proposes the robot-based remote laser welding system as a means of resolving the limited welding speed and accuracy of conventional laser welding systems.

In the paper basic knowledge of thorn pile and the working principle characteristics are introduced in different directions. Mechanical equilibrium conditions of thorn pile are that Adjacent to the piston must be each other angle of 60 °and Hydraulic cylinders are assembled In the longitudinal. The paper laid the foundation for the design and use of thorn pile extrusion forming machine.

This paper introduces a rotor design technique for a turbo blower supported by magnetic bearings that considers the critical speeds of the rotor. An important factor for rotor critical speeds is the stiffness of its bearings. The magnetic bearing acts as a negative spring, called the position stiffness prior to operation, and rotor systems are initially unstable until the stiffness (current stiffness) and damping in the active control rotating system are determined using closed loop control forces. This paper describes a finite element model for the rotor, derives the stiffness equations for the magnetic bearing, and defines the total magnetic bearing stiffness including the position stiffness and current stiffness. Finally, the magnetic bearing stiffness that avoids the rotor critical speeds is chosen.

The deformation of the spindle system is the main factor affecting the accuracy of ultra-high speed grinding. To calculate the deformation of ultra-high-speed grinding spindle system is required to consider not only the formation of structural deformation, but also the thermal deformation. Using the simulation method, oil temperature and grinding force are calculated in this paper. Based on these two factors, the thermal-mechanical deformation of the hybrid spindle system is analyzed and calculated with the method of FEM. the This article uses simulation methods, analysis and calculation of the oil film temperature rise and the grinding force caused by deformation of the liquid and hydrostatic spindle system factors. The methods presented in this paper can be used in digital design of various kinds of spindle systems, in order to improve the accuracy of the spindle system design.

Electrostatic precipitator is a kind of important dust collecting equipment. The rapping acceleration is the standard of electrostatic precipitator design and manufacturing. The aim of the work reported in this paper was find a new method for solving the rapping acceleration. Based on the numerical analytical method and the dynamic display algorithm, this paper is to build a new method for solving the rapping acceleration of electrostatic precipitator by using finite element method. By comparing the results of finite element method and the model test data and analyzing calculation results, this method is proved to be correct and effective. Using this method in the analyzing of practical equipment, the result basically tallies with the actual result. The finite element method can be used conveniently in different plate profiles, different ways of hanging, striking hammers and different methods of rapping. So the finite element method has an important practical significance in the analyzing of existing plate and the researching of new plate.

The purpose of this paper is to find the optimum design attack angle for fixed-pitch variable-speed wind turbine blade design, given the base-line wind turbine and the blade airfoil. Aerodynamic characteristics, i.e. lift and drag coefficients and lift to drag ratio, of the wind turbine, are analyzed. Two design attack angles along with the base-line attack angle (with maximum lift to drag ratio) are selected for the wind turbine blade design exercise. Blade design outcomes are analyzed and compared along with load performance and power performance. This paper is possibly the first attempt to determine the optimized design attack angle for maximizing annual energy production, given the base-line wind turbine and the blade airfoil.

The paper sets up the Finite Element Model on the basis of crankshaft fillet rolling experiment and its mechanism. And then the paper shows the distribution of the residual stress in different depths of rolled crankshaft fillet through numerical simulation. It is found that the fatigue strength can greatly be produced by the method of the engine crankshaft fillet rolling in most of fillet areas; Simultaneously, two strips of tensile stress which is related to reduce the crankshaft fatigue strength will be generated in the peripheries. The tensile stress strips only emerge in the surface layer of the fillet, and then mainly disappear in the depths of 0.4mm below the surface layer. The paper concludes that the main reason of strips of tensile stress lies on the transition between the deformed region and the non-deformed reformed region after trolley wheel pressure is imposed on through a further research.

The main heat source of the spindle system of CNC machine tool has been analyzed. The friction heat of the motor as well as the bearing has been calculated. This paper established the finite element model of the spindle system of a precise CNC turning center, and used ANSYS to analyze the steady temperature field of the spindle system and the thermal deformation of the spindle. Finally, this paper proposed a solution to install a cooling sleeve in front of the spindle box, which can apparently reduce the thermal error of machine spindle.

Design of vertical bearing member under the isolation devices needs higher safety reliability in the base-isolation system, which is more important than the upper structure. A method of considering second-order moment caused by superstructure horizontal shift is put forward in this paper, so that to analysis the stress and strain in the FEM of cantilever column under the isolators. Analysis result of the FEM indicates that the method in this paper can effectively balance the decrease of stiffness, which is caused by the shift of superstructure on the isolators

In order to develop the innovative and applied talents of students, this paper designed an experiment of composite beam bending by transverse force on the basis of the single material and pure bending beam .The calculation model of the simple beam bearing a concentrated force at the beam’s midspan was adopted. Based on this model, this paper discussed the theory calculation and made the corresponding experimental layout and got some experimental data.Compared the experimental data with the results of theoretical calculation，students can strengthen their perceptual knowledge for composite materials beams,and arouse their Learning enthusiasm and train the ability of solving engineering problems.

This paper introduces the FEA method for modal analysis of aero-engine turbine blade-disc system. Natural modal analysis for dynamical analysis and the result can be used as criterion of many dynamics characteristics and further analysis. In this paper, the natural modal of an aero-engine turbine blade-disc system with the turbine joint hole fully constrained and in free status is calculated respectively. And the first ten natural frequencies and mode shapes are obtained. Also, vibration characteristics of each natural modal and the corresponding influence on turbine blade-disc system and other structure are discussed. The analysis method and results in this paper can be used for further study on optimal design and vibration safety verification for the blade-disc system.

In order to study a novel laser indirect shock forming mechanism which applies laser-driven flyer to load the workpiece, this paper uses the SPH method to study the behavior of laser indirect shock forming and simulate the process of the workpiece forming. The SPH method solves the problem about the mesh tangling encountered in extreme deformation and this paper presents some ideal results and histories. Through comparing the experiment result with the simulating result, it is easy to find that the analysis with the SPH method can predict the final shape of workpiece properly. To some extent, this paper could provide some helpful messages for the study on the novel laser indirect shock forming.

Spherical plain bearing was applied widely in industry. In the paper, with the finite element code Abaqus, a sequentially coupled, 3D, and thermal-mechanical finite element analysis model of the bearing system was built up based on the theories of heat transfer, tribology and composite material mechanics. The paper focused on effects of the mean sliding velocity and the load. In the end, the paper mentioned a simulation method of computing wear.

The question of the pretensioning force of the wrapping wires for a suspension bridge is one of the important subjects. It could prevent the main cable from eroding by air or chemicals. And it must have some loss under the influence of dead loading, each mobile load and environment[1]. Now, the research of wrapping wire of the main cable is not much at home and abroad. And wrapping wire tension is mainly obtained depending on engineering experience. This paper has an experiment about the wrapping wire of Yangmingtan Bridge in Harbin to draw conclusions that wrapping wires tension which is 2m far from the cable clips is reduced extensively, more than 80%. But the residual tension, 8m from the cable clips, is about 35% of the initial tension. In addition, the wrapping wires tension which is about 93cm far from pre-wrapped wire-loops remains stable. Finally, starting from calculation theory, the paper puts forward that the wrapping wire tension should be 2.0kN.

This paper presents a method that using inner transverse prestressing bars to enhance the shear capacity of concrete beams, which can be used in new transformer beams to decrease the sectional dimensions. Four transversely prestressed concrete beams and one ordinary reinforced concrete beam were tested. The nonlinear finite element method was applied to analyze them, and the following conclusions can be drawn: (a) The transverse prestressing bars can efficiently increase the shear capacity and failure load of the reinforced concrete beam, the improvement effect is more obvious when exerting the prestressing force on them properly. (b) On the whole, the simulated load-deflection relationships and failure loads of the five specimens agree well with the corresponding tested load-deflection relationships and failure loads. It indicated that the FE models used in this paper predict the structural behavior of the transversely prestressed concrete beams satisfactorily. (c) From the contour of first principal stress, it can be seen that the transverse prestressing bars can efficiently enhance the shear crack resistance of the reinforced concrete beams, if the area of transversely prestressing bars is almost same, the transverse bars with smaller diameter and smaller spacing will be better. It agrees well with the test results.

In some circumstances, huge mass, if not cushioned, may pull the piston to a halt at rod side or head side at ease with a tremendous velocity causing huge impact. As a result of this issue, the boom cylinder of hydraulic excavator provides cushioning apparatus at the rod side stroke end. This paper discusses and analyses the cushioning apparatus structure of boom cylinder, and then proposes a numerical simulation model with SimulationX. It is known to us that many dynamic parameters of boom cylinder vary as mechanical structure or motion of excavator attachment changes. Thus in order to study the relationship between kinetic parameters and cushioning capability of boom cylinder, an excavator attachment model is built next. The last part of this paper is devoted to the obtained simulation results.

This paper proposes a new type of internal meshing cycloid rotor pump-Double enveloping cycloid pump. It is characterized by double contact lines between the inner and the outer rotor so that it has outstanding advantages, such as better sealing capacity, higher outlet pressure and volumetric efficiency etc. Based on the brief introduction of the equations of the inner and the outer rotors’ tooth profile, the composition and characteristics of the outer rotor’s tooth profile for the double enveloping cycloid pump are discussed in detail, the calculation method of the normal meshing clearance between the outer rotor and the modified inner rotor is introduced, and the calculation example is given. Result shows that the works in this paper will help to design the new type cycloid rotor pump with high performance.

The key components of the single screw compressor are rotor screw and two star-wheels which are symmetrical arrangement. The rotor screw and two star-wheels have composed a special spatial meshing pair. The high meshed precision is the guarantee of its excellent performance. In this paper, we will study the milling technology of screw milling cutter to the rotor screw, and establish the finite element model of the cutter, and analyze the cutter’s stress situation during the milling process, make the cutting parameters of the screw optimization, In this paper, we will also study the influence of the Milling depth and cutting width to tool in displacement and stress, in order to provide a theoretical reference of selecting of appropriate cutting parameters ,improving of processing quality and reducing wear of the tool.