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This paper aims to research the tribological and dynamic characteristics of aeroengine hybrid ceramic bearings through wear experiments and simulation analysis.

First, the authors carried out wear experiments on Si₃N₄–GCr15 and GCr15–GCr15 friction pairs through the ball-disc wear test rig to explore the tribological properties of their materials. Second, using ANSYS/LS-DYNA simulation software, the dynamic simulation analysis of hybrid bearings was carried out under certain working conditions, and the dynamic contact stress of all-steel bearings of the same size was simulated and compared. Finally, the change of the maximum contact stress of the main bearing under the change of load and rotation speed was studied.

The results show that the Si₃N₄–GCr15 pair has better tribological performance. At the same time, under the conditions of high speed and heavy load, the simulation analysis shows that the contact stress between the ceramic ball and the raceway of the ring is smaller than the steel ball. That is, hybrid bearings have better transient mechanical properties than all-steel bearings. With the speed increasing to 12,000 r/min, the maximum stress point will shift in the inner and outer rings.

In this study, the tribological and transient mechanical properties of Si₃N₄ material were comprehensively analyzed through wear experiments and dynamic simulation analysis, which provided a reference for the design of hybrid bearings for next-generation aeroengines.

Presents a review on implementing finite element methods on supercomputers, workstations and PCs and gives main trends in hardware and software developments. An appendix included at the end of the paper presents a bibliography on the subjects retrospectively to 1985 and approximately 1,100 references are listed.

Aiming at the unbalancing problem of the neutral equilibrium characteristic for balance hoist in the loading process, the purpose of this paper is to establish a dynamic equation for multi-body using the Lagrange method. It is not difficult to find that the deformation of the boom system has a great influence on the stability of the whole system, through the simulation analysis of the multi-rigid-body system model.

Aiming at the unbalancing problem of the neutral equilibrium characteristic for balance hoist in the loading process, the dynamic equation for multi-body is established by Lagrange method. It is not difficult to find that the deformation of the boom system has a great influence on the stability of the whole system, through the simulation analysis of the multi-rigid-body system model.

Result shows that different weights have a great influence on the force deformation and vibration of the boom system of balance hoist. With the increase in lifting weight, the force and deformation of the boom system increase; lead to balance hoist unique with characteristics of indifferent equilibrium, proportional amplification, labor-saving operation will be lost, easy to cause the imbalance of balance hoist. Therefore, the appropriate increase in the basic length of the compression bar, reduction in the basic length of the tension rod and the increase stiffness of the boom system can improve the stability of balance hoist, which provides a reference for the optimization and manufacture of the balance hoist structure.

The simulation model was established by analyzing the working principle and the load condition of the balance hoist, and the simulation and dynamic characteristics of three typical working conditions are analyzed by using ADAMS; result shows that different weights have a great influence on the force deformation and vibration of the boom system of balance hoist. With the increase in lifting weight, the force and deformation of a boom system increase, lead to balance hoist unique with characteristics of indifferent equilibrium, proportional amplification, labor-saving operation will be lost, easy to cause the imbalance of balance hoist.

Despite the advantages that the VoFI approach offers compared with traditional capital budgeting methods, its application for the appraisal of information technology (IT) and information systems (IS) investments in both research and practice is not widespread to date. Given the static nature of the generic VoFI table, the method reaches its limits in its financial plan form because it is unable to investigate the dynamic behaviour of complex investment calculations. To date, there has been no attempt to address these shortcomings to advance the use of VoFI as a useful and valid capital budgeting method in finance and accounting. Therefore, the purpose of this study is to address this research gap and aim at developing a ‘dynamic’ VoFI model that integrates all input variables and target measures of a VoFI table and visualises the causal relationships among these variables.

The ‘dynamic’ VoFI model is developed through System Dynamics (SD) modelling to enhance the strength of the VoFI concept as an instrument for visualising the financial implications of investments in IT and IS at the corporate level. Case study research is used as a research method to study the behaviour of the developed model. The validity of the model is demonstrated by conducting simulation runs in Vensim software. In addition, probabilistic sensitivity analyses are performed to account for the impact of uncertainty on the main model variables.

The results demonstrate the usefulness of SD modelling for extending the generic VoFI concept by integrating risk analyses and providing a new strategy of data analysis and data presentation different from the typical financial plan form. Furthermore, the dynamic VoFI model enables the visualisation of interdependencies among the various variables incorporated in the VoFI financial plan, which significantly enhances the conceptual understanding of the investment and its financial consequences.

The integration of the VoFI concept into an SD model helps researchers and practitioners to enhance their conceptual understanding of this method. This thus increases its acceptance and popularity as a practical capital budgeting method, especially for the financial assessment of IT and IS investments. The VoFI model proposed in this paper should also enable analysts and decision makers to become more conscious of the interdependencies between the assumptions made for an appraisal and the quantitative results.

The purpose of this paper is to present a study of radial aircraft tire for safety assessment during various scenarios.

A detailed finite element (FE) model of aircraft tire was established based on the actual geometry of the target tire for numerical simulations. As the major component of this tire, rubber material usually presents a complicated mechanical behavior. To obtain the reliable hyperelastic properties of rubber, a series of material tests have been processed. Moreover, in order to validate the proposed model, the simulations results of inflation and static load scenarios were compared with the experimental results. Both of the control volume and corpuscular particle method methods were used in the numerical simulations of aircraft tire.

The comparisons of the two methods exhibit close agreement with the experimental results. To assess the safety of aircraft tire during the landing scenario, the dynamic simulations were processed with different landing weights and vertical landing speeds. According to the relevant airworthiness regulations and technical documents, the tire pressure, deflection and load have been chosen as the safety criteria. Subsequently, the analysis, results and comments have been discussed in detail.

The validated FE model proposed in present study can be effectively used in tire modeling in static and dynamic problems, and also in the design process of aircraft tire.

This paper aims to present numerical simulations for a series of flight processes for the postlaunching stage of the “balloon-borne UAV system.” It includes the balloon further ascent motion after airborne launching. In terms of unmanned aerial vehicles (UAVs), the tailspin state and the charge-out process with an anti-tailspin parachute-assisted suspending are analyzed. Then, the authors conduct trajectory optimization simulations for the long-distance gliding process.

The balloon kinematics model and the parachute Kane multibody dynamic model are established. Using steady-state tailspin to reduced-order analysis and achieving change-out simulation by parachute suspension dynamic model. A reentry optimization control problem is developed and the Radau pseudo-spectral method is used to calculate the glide trajectory.

The established dynamic model and trajectory optimization method can effectively simulate the motion process of balloons and UAVs. The system mass reduction for launching UAVs will not cause damage to the balloon structure. The anti-tailspin parachute can reduce the UAV attack angles effectively. The UAV can glide to the designated target position by adjusting the attack angle and sideslip angle. The farthest flight distance after launching from 20 km height is 94 km and the gliding time is 40 min, which demonstrates the potential application advantage of high-altitude launching.

The research content and related conclusions of this article achieve a closed-loop analysis of the flight mission chain for the “balloon-borne UAV system,” which provides simulation references for relevant balloon launching experiments.

This paper establishes a complete set of numerical simulation models and can effectively analyze various postlaunching behaviors.

The last 60 years have seen Australia and the United Kingdom diverge, both socially and economically. This paper considers how the widening social gap between the two countries is reflected by their respective redistributive systems. The analysis is based upon two microsimulation procedures – one static and the other dynamic – both of which are used to consider the probable distributional effects that would arise if elements of the Australian and UK tax and benefits systems were exchanged. The static microsimulation analysis presented suggests that comparisons based purely upon cross-sectional survey data are affected by population heterogeneity, which tend to overstate the redistributive effect of the Australian transfer system relative to the UK. Nevertheless, the dynamic microsimulations suggest that, on balance, the Australian transfer system is more redistributive than the UK system, and reflects a greater concern for redistribution between households. The UK system, in contrast, reflects a greater concern for redistribution through the life course.

The purpose is to develop and apply a systematic simulation approach for dynamic analysis in order to study a two combustion chambers liquid propellant engine.

The logic of the simulation method and the software is based on following the liquids. The implicit nonlinear algebraic equations are solved using a number of nested Newton‐Raphson loops, and the nonlinear and time varying differential equations are solved using a first‐order Euler technique.

It is found that the developed simulation code predicts the steady‐state values with errors under 5 percent, and this code has the capability to be used in studying the effect of various elements and subsystems parameters on the forecasting the performance and operation of the engine system.

At present, the research is limited to a specific liquid propellant engine. Development of a general purpose software package for simulation of liquid propellant engines, based on the developed simulation algorithm, is subject of future research.

The major outcome of this research is that verifies liquid engine simulation code may be used as a suitable tool to optimize the engine.

This is the first paper in the area of a two combustion chambers engine simulation and dynamic analysis that is based on the application of an existing simulation algorithm.

The purpose of this study is to integrate modern decision sciences and develop a dynamic risk management model for international alliance engineering design projects.

To apply the model to real-world risk assessment and managerial decision-making, a mega project case study was conducted. System dynamics and computer simulations were used for improving quantitative analyses and scenario planning.

Based on the consideration and analyses of different cooperation risk factors, ripple effects of design error is found to be the key factor of subcontract management in international alliance projects in this study.

This study provides a rationale for dynamic risk management decisions and enables international alliance companies to systematically control the cooperation risks in the execution of projects.

In the dynamic project management process, a significant increase in the design error rate does not unilaterally occur but is caused by subcontract and other management errors as a system problem. Integrative solutions with systems thinking would help the management.

This study proposed a framework of measuring project performance and dynamic risk management. The benchmarked case study demonstrates the capability of the proposed model for the feedback learning of business lessons and knowledge accumulations.