Applied Mechanics and Materials Vols. 457-458

Abstract: In this paper, the finite element analysis is made to the modal analysis of the impeller, a finite element model of a impeller with cracks was established. This paper presents results of the modal of the compressor blade subjected to centrifugal force and aerodynamic equilibrium pressure. In this analysis, the numerical models without defects and also with cracks were defined. The simulation results showed that the centrifugal force due to rotational speed can greatly influence the frequency of the impeller. The distribution of two cracked blades effect the natural frequence of the impeller. When two cracked blades locate in the interval position, the increasing value of frequence is maximum. When the two cracked blades interval 150°, the increasing value of frequence is minimum. It provides a basis for modal calculation of the impeller.

Abstract: Existing piston gas provers use a single piston cylinder as standard which replace the standard flow of gas by the piston moving at a constant speed. In order to solve the problem that the piston proverflow ceiling is limited by the volume of piston cylinder, we have developed a double-piston gas prover. Firstly, the article introduces the devices principle and mathematical model simply. Then it presents a series of experiments and experiments results of the device. Finally,the paper analyzes the uncertainty of the equipment. The results show that the double-piston gas prover is available.

Abstract: Combining with change of the thermal physical parameters of materials, the temperature field of 45 steel gears in quenching processes has been numerically simulated using the thermal analysis module of ANSY Workbench software. The relationship between temperature of gears parts and quenching time has been achieved, the simulation results are consistent with actual process. The methods is superior to the traditional manual measuring and experience judgment way. The simulation process has provided the due theoretical basis for the calculation of parts thermal stress and residual stress in quenching process.

Abstract: In this paper, for the large scale production demand of waveform spring, it combines UG advantage of complex surface modeling and computer numerical control (CNC) machining, uses this way of surface modeling method of bicubic B-spline to establish the stamping die geometry model for the need of waveform spring production. And from a process point of view, it analyzes the key issues of die CNC machining to achieve the selection of optimal small tool radius, tool path rational planning and rough finishing parameters set. The application results show that: the shape precision of die surface could meet the design requirements and could achieve the precision stamping of waveform spring.

Abstract: The innovative value chain system and the operation mechanism were studied of the service enhanced construction. In the service enhanced construction era, value chain innovation system includes orientation system integration services, full life cycle project management and engineering general contracting system. The service enhanced construction needs perfect construction market environment, the trust and sharing information in business, coordinated management and knowledge management, to reconstruct the value chain system, to achieve the structural adjustment of the construction industry and to improve the core competitiveness of enterprises.

Abstract: Inflatable structures are widely used in aerospace engineering. They should keep a certain configuration in service, and their mechanical properties are closely related to their configurations. It is essential to investigate the ability of maintaining configuration of inflatable structures in order to study their mechanical properties . The concept of shape retention was first proposed in this paper. Besides, a shape retention index which quantitatively depicts the concept was given for inflatable column structures. The index takes compressive deformation and compression force into account. It is demonstrated that the shape retention increases with the increase of the modulus of the membrane and the inner pressure of inflatable structures.

Abstract: Hinge sleeve of cubic press is the most important equipment which is used in the field of processing and production of super-hard materials, and is always under super high pressure, so the problem of fatigue must be concerned. In this paper, Actual model of hinge sleeve of cubic press was established in ANSYS. Strength of hinge sleeve of cubic press was calculated under super high pressure load in realistic condition, which the equivalent stress contours were obtained, and the danger point was found out. Then the fatigue analysis was carried out to this danger point by applying ANSYS/Fatigue module. Consequently the fatigue usage coefficients were obtained.

Abstract: 3-D model of the lathe tool fixture and tool carrier in\ CNC Machine Tool for guide disc is established through Solidworks. Then, the 3-D model is input into ANSYS, simulating the stress map and the nephogram of displacement deformation of the lathe tool fixture and tool carrier, which plays a important role in designing the lathe tool fixture and tool carrier.

Abstract: Stress corrosion cracking (SCC) is one of the key issues of welded structure failure in nuclear power plants. To understand the effect of strength matching on SCC growth rate in welded joint of primary coolant circuit safe end in pressured water reactor, a model of the safe end welded joint with mismatched strength was established by using elastic-plastic finite element method (EPFEM).The effect of weld strength matching on SCC growth rate was analyzed in this paper, by adopting crack tip strain rate as SCC mechanical driving force. The investigated results indicate that the distribution of plastic strain and plastic strain rate nearby the crack front is similar when the crack located at welded metal, and the driving force of SCC along the crack front in the over-match, even-match and under-match welded joint are from small to large, respectively, which implicit SCC growth rate along the crack front in the over-match, even-match and under-match welded joint also are from slow to fast, respectively. The investigating establishes a foundation for improving the predicting capability of SCC growth rate in nuclear power structures.

Abstract: The active bearings with variable damping and stiffness are important for vibration isolation in wide frequency excitation. A model of vertical isoaltion system via magnetorheological (MR) bearings was built. Based on analyzing the characteristics of MR grease and MR elastomer, an MR parallel-isolator was designed to instead the passive bearing.Then an adaptive particle swarm optimization (PSO) was adopted to adjust the parameters of MR bearing. A vertical MR isoaltion experiment was proposed. Results demonstrate that MR bearings have better performance than passive bearing in concurrently restraining force transmissibility and vibration acceleration.