In this work, a novel morphing machining strategy (MMS) is proposed. In the method, the workpiece is progressively carved out from the stock. Pitfalls in conventional iso-height strategy, such as sharp edges and unevenly distributed left-over materials, are overcome. Moreover, to calculate different levels in the MMS, an energy-based morphing algorithm is proposed. Finally, the proposed strategy is employed in the machining of artificial bone represented by a T-spline surface. The excellent properties of T-spline, such as expressing complex shapes with a single surface, have been well adopted to artificial bone fabrication. Computer simulation and the actual machining of the middle finger bone show the feasibility of the proposed strategy.

To improve lubrication effect and seal performance, complicated geometrical hydrodynamic grooves or patterns are often processed on end faces of liquid lubricated mechanical seals. These structures can lead to difficulties in precisely estimating the seal performance. In this study, an efficient adaptive finite element method (FEM) algorithm with mass conservation was presented, in which a streamline upwind/Petrov-Galerkin (SUPG) weighted residual FEM and a fast iteration algorithm were applied to solve the lubrication equations (Reynolds equation). A mesh adaptation technique was utilized to refine the computation domain based on a residual posterior error estimator. Validation, applicability, and efficiency were verified by comparison among different algorithms and by case studies on seals’ faces with different groove structures. The study investigated the influence of the order of shape function and the mesh number on the leakage balance. Mesh refinement occurred mainly in cavitation zones when cavitation happened, otherwise it occurred in regions with a high pressure gradient. Numerical experiments verified that the proposed algorithm is a fast, effective, and accurate method to simulate lubrication problems in the engineering field apart from end face seals.

Hypersonic vehicles subjected to strong aerodynamic forces and serious aerodynamic heating require more stringent design for an infrared window. In this paper, a finite element analysis is used to present the distributions of thermal and stress fields in the infrared window for hypersonic vehicles based on flowfield studies. A theoretical guidance is provided to evaluate the influence of aerodynamic heating and forces on infrared window materials. The aerodynamic heat flux from Mach 3 to Mach 6 flight at an altitude of 15 km in a standard atmosphere is obtained through flowfield analysis. The thermal and stress responses are then investigated under constant heat transfer coefficient boundary conditions for different Mach numbers. The numerical results show that the maximum stress is higher than the material strength at Mach 6, which means a failure of the material may occur. The maximum stress and temperatures are lower than the material strength and melting point under other conditions, so the material is safe.

This paper deals with a correction method for corrosive crack width caused by non-uniform corrosion. Considering the corrosion cracking characteristics of a reinforced concrete structure, a correction model of corrosive crack width involving the mutual impacts between adjacent measuring points is established. The calculation model for steel bar corrosion rate for single point is obtained through quantitative analysis and accelerated corrosion tests on more than 70 reinforced cubic members. Two methods are suggested by combining two models, the correction and the corrosion calculation ones. Electrolyte accelerated corrosion tests on seven beams are carried out to verify these methods. The experimental results show that the ratio between the maximum corrosion rate by the indirect method and the measured average value ranges from 1.4 to 2.4, and the indirect method is shown to be an effective method for calculating the maximum corrosion rate.

A new contraction joint element model for the interface in different meshes between the arch dam sections is constructed. The study on the elastic-plastic damage constitutive model for concrete, which is applied to multi-axial stresses, is also taken. The models of the dam-foundation-reservoir system for Xingbiling and Jinping concrete arch dams, China are calculated using the proposed contraction joint elements and the elastic-plastic damage constitutive model to verify the proposed models. Results showed that the proposed contraction joint element model has a high precision in simulating the behavior of contraction joints and the elastic-plastic damage constitutive model has a high precision in simulating the behavior of the damage to the concrete.

Recent years have seen a surge in assessment of potential impacts of climate change. As one of the most important tools for generating synthetic hydrological model inputs, weather generators have played an important role in climate change impact analysis of water management. However, most weather generators like statistical downscaling model (SDSM) and long Ashton research station weather generator (LARS-WG) are designed for single site data generation. Considering the significance of spatial correlations of hydro-meteorological data, multi-site weather data generation becomes a necessity. In this study we aim to evaluate the performance of a new multi-site stochastic model, geo-spatial temporal weather generator (GiST), in simulating precipitation in the Qiantang River Basin, East China. The correlation matrix, precipitation amount and occurrence of observed and GiST-generated data are first compared for the evaluation process. Then we use the GiST model combined with the change factor method (CFM) to investigate future changes of precipitation (2071–2100) in the study area using one global climate model, Hadgem2_ES, and an extreme emission scenario RCP 8.5. The final results show that the simulated precipitation amount and occurrence by GiST matched their historical counterparts reasonably. The correlation coefficients between simulated and historical precipitations show good consistence as well. Compared with the baseline period (1961–1990), precipitation in the future time period (2071–2100) at high elevation stations will probably increase while at other stations decreases will occur. This study implies potential application of the GiST stochastic model in investigating the impact of climate change on hydrology and water resources.