We have developed an integrated software system, TrakRF, to model electromagnetic fields and charged particle orbits in high-power RF devices. Our primary application is simulation of electron multipactoring near RF vacuum windows for the APT (Accelerator Production of Tritium) Program. In this paper we describe features of the codes and initial multipactor calculations for superconducting cavi...

We study the approximation properties of some general finiteelement spaces constructed using improved graded meshes. In our results, either the approximating function or the function to be approximated (or both) are in a weighted Sobolev space. The finite-element spaces that we define are obtained from conformally invariant families of finite elements (no affine invariance is used), stressing t...

A numbers of important developments have led to an increasing attractiveness for very high speed electrical machines (either motor or generator). Specifically the increasing switching speed of power electronics, high energy magnets, high strength retaining materials, better high speed bearings and improvements in design analysis are the primary drivers in a move to higher speed. The design chal...

In this paper, a multiscale modelling strategy is used to study the effect of grain-boundary sliding on stress localization in a polycrystalline microstructure with an uneven distribution of grain size. The development of the molecular dynamics (MD) analysis used to interrogate idealized grain microstructures with various types of grain boundaries and the multiscale modelling strategies for mod...

High-energy absorption and light-weightiness are two critical properties for impact protection in the aerospace sector. In past, use of periodic honeycomb structures or random porous metallic foams were preferred route to obtain a good specific-energy performance. recent years, additive manufacturing has increased design freedom creating new generation reticulated materials: metamaterials latti...

A Galerkin finite-element model of the shallow-water equations on a limited domain is presented. The evolutionary equations of continuity and momentum are coupled at each time step using an extrapolated Crank-Nicolson method to quasilinearize the nonlinear advective terms. The coupling allows time steps to be used larger than those possible with an uncoupled model. A linear one-dimensional stab...

The coupled heat and moisture actions could easily cause deformation, cracking corrosion problems in the slab ballastless track under operational conditions via China Railway Track System (CRTS) Ⅱ. In this paper, two one-quarter-scaled models of CRTS Ⅱ hygro-thermal environment were tested a testing chamber, respectively. To study effect constrained on structural performance structure, temperat...

The primary objective of this study was to assess the pavement structural deterioration based on Non-Destructive Test (NDT) data using an Artificial Neural Networks (ANN) based approach. ANN-based prediction models were developed for rapid determination of flexible airfield pavement layer stiffnesses from actual NDT deflection data collected in the field in real time. For training the ANN model...

We study the approximation properties of some general finiteelement spaces constructed using improved graded meshes. In our results, either the approximating function or the function to be approximated (or both) are in a weighted Sobolev space. The finite-element spaces that we define are obtained from conformally invariant families of finite elements (no affine invariance is used), stressing t...