Applied Mechanics and Materials Vol. 482

Abstract: As underground structure, the tunnel itself has good anti-seismic performance, but in recent years, according to a large number of investigation data about the earthquake disaster for tunnel, we find that the tunnel passing through the fault fracture zone is quite easy to be destroyed seriously. Therefore, developing dynamic response analysis and shock absorption measures has great practical significance. According to the characteristics of tunnel passing through fault and the tunnel depth, considering a certain proportion relationship in finite element model, the analysis model for tunnel seismic joint is established. Finally comparing the results comprehensively, we discuss the effect of the different setting location and setting separation distance of seismic joint to seismic response of tunnel passing through fault. From the work we have done, we get the seismic joint which is good for tunnel seismic resistance. This method is expected to be adopted as reference to the similar projects.

Abstract: To study the influence law of fastener stiffness match on subway rail switch safety, and select appropriate stiffness, the No.9 subway switch was taken as an example in this paper to carry out all the following work. Based on finite element method, the influence of fastener stiffness match on the vertical dynamic relative displacement of switch rail and dynamic gauge widening were analyzed. The result shows that: the design concept of 'soft upper and rigid lower' can effectively decrease the vertical relative displacement of switch rail, and avoid the load of switch rail in advance, and ensure the safety of structure strength; It also could slow down dynamic gauge widening and serpentine movement amplitude, and improve the safety and stability of train; To ensure the safety of train, the design conception of soft upper and rigid lower should be applied for the subway switch.

Abstract: S Bridge is a suspension bridge constructed in 1996 (154m+452m+154m). This paper took the bridge as a background, and analyzed whether it could meet the technical requirements, thus providing a reference for the safe operation of the bridge. The results show that the bearing capacity of main girder, the sling stress and the safety factors of main cables meet code requirement, but the stress of stiffening girder concrete exceeds the code limits, meanwhile, the impact of temperature gradient load on stiffening girder is relatively large.

Abstract: Use of cantilever plate and the fixed plate’s end moment formulas can obtain the value of the plate end moment which is increased, and then you can determine the reinforcement.Considered the differential settlement,an existing project is well solved, use the simple analysis to quickly identify the projects’ suitable means of connection.

Abstract: A growing number of applications are calling for the compact laser sources operating in the 2~5μm, which is called the mid-infrared spectral region. In general, a laser beam is attenuated, broadened, defocused and may even be deflected as it propagates through the atmosphere. In this paper, the transmission characteristics of mid-infrared laser which covers the whole 2~5μm spectral band are theoretical analyzed, and the computational simulation results are given.

Abstract: The aircraft/engine integration design numerical simulation model was established. The engine design performance specifications were obtained by calculating aircraft lift-drag characteristics, mission analysis, constraint analysis. Combining engine cycle parametric analysis with installation loss computing, the engine performance parameters can be found, which meet the aircraft flight envelope performance requirements. Taking double bypass variable cycle engine as an example to check the model, the results show that the variable cycle engine can meet aircrafts thrust and fuel consumption demands under different operating conditions, and achieve cruise thrust adjustment at the same inlet mass flow to reduce installation losses.

Abstract: Infrared stealth is of great importance to increase the survival ability of the aircraft. The exhaust system is the main radiation source of the aircraft at the rare hemisphere. A program using reverse Monte-Carlo method was developed to calculate the infrared radiation intensity of afterburning turbofan engine under non-afterburning condition, and simulate axisymmetric nozzle and three S-shaped nozzles with different relative eccentric distances. The results demonstrate that: the infrared intensity of S-shaped nozzle is much lower than that of axisymmetric nozzle; S-shaped nozzle can effectively reduce the maximum of IR intensity in the rear hemispheric space; the S-shaped nozzle with the relative eccentric distance of 0.5 can reduce the intensity of infrared radiation in critical detection directions effectively.

Abstract: In order to satisfy the application of space science, space-based remote sensing and environmental monitoring in our country, a value model is proposed for distributed reconfigurable satellite system life cycle value assessment in this paper. Besides, many uncertain factors of multi-aspects are considered in this model. The value model is transferred into value assessment tool by means of programming. In addition, the distributed reconfigurable satellite system developed by this tool and the corresponding value assessment system can be applied to space-based application system which is the current technology of the distributed reconfigure satellite system.

Abstract: For the problem of module division for distributed reconfigurable satellite system. A satellite function tree top-down is set up in this paper. And the genetic algorithm was applied in the module division. Finally the entire satellite was decomposed into various standard parts. In practice, users only need to combine those standard parts into a specific function module according to the requirements. Then send those modules into their orbit. And those modules through the way of formation flight, wireless connection to fulfill the task. Considering China's space development strategy, satellite systems long life and high reliability, upgrading, expansibility, satellite systems planning, running, production all kinds of uncertainty factors. Finally the satellite system was divided into 15 standard parts.

Abstract: A coupled fluid, thermal and structure analysis model was established for solid rocket motor nozzle. Based on a steady flow simulation and a transient thermal simulation, a transient structure analysis simulation was executed. The model took a frictional coefficient 0.3 into account to simulate a rub action between the parts of the nozzle. Result showed that with a frictional coefficient, Von Mises stress could be released which gives a constructive recommendation for a structure simulation of a nozzle. Also, the model was more close to the actual. A more dependable approach was introduced and it could contribute to designing department.