The aim of this paper is to numerically investigate cooling performances of a non-film-cooled turbine vane coated with a thermal barrier coating (TBC) at two turbulence intensities (Tu = 8.3% and 16.6%). Computational fluid dynamics (CFD) with conjugate heat transfer (CHT) analysis is used to predict the surface heat transfer coefficient, overall and TBC effectiveness, as well as internal and average temperatures under a condition of a NASA report provided by Hylton et al. [NASA CR-168015]. The following interesting phenomena are observed: (1) At each Tu, the TBC slightly dampens the heat transfer coefficient in general, and results in the quantitative increment of overall cooling effectiveness about 16–20%, but about 8% at the trailing edge (TE). (2) The protective ability of the TBC increases with Tu in many regions, that is, the leading edge (LE) and its neighborhoods on the suction side (SS), as well as the region from the LE to the front of the TE on the pressure side (PS), because the TBC causes the lower enhancement of the heat transfer coefficient in general at the higher Tu. (3) Considering the internal and average temperatures of the vane coated with two different TBCs, although the vane with the lower thermal conductivity protects more effectively, its role in the TE region reduces more significantly. (4) For both TBCs, the increment of Tu has a relatively small effect on the reduction of the average temperature of the vane.

Peridynamic theory has recently shown to be a versatile tool for simulating complex phenomena related to the fracture and fragmentation of structural and composite materials. We introduce a novel failure criterion based on the classic stress tensor which takes inspiration from an approach proposed in the literature. Differently from the classic critical stretch-based failure criterion used in peridynamics, our approach takes into account the total elastic energy stored in the bond allowing to predict with more accuracy problems that involve mixed-mode I-II fracture. In order to show the effectiveness of the proposed failure criterion, a benchmark fracture problem is analyzed showing a good agreement with the experimental results and the numerical results obtained with other numerical methods.

Topology Optimization (TO) is a mathematical method extensively employed to optimize material layout within the design space, for a given set of boundary conditions with the goal of maximizing the performance of the system. This process takes a three-dimensional design space and whittles material away within it to achieve the most efficient design. Currently, engineers use this mathematical approach at a concept level of a design process, leading to results which are often fine-tuned for manufacturability. In some cases, the optimized geometry can be directly manufactured using additive manufacturing, indeed, TO is a key part of design for additive manufacturing. This work aims to apply TO in order to minimize the mass of an engine gearbox while maintaining an acceptable mechanical performance when compared to the original design. Numerical simulations are carried out by means of CAD and FEM software in order to improve the design of an aircraft gearbox composed of four gears, therefore, irrelevant parts of material are removed in the design space to meet the goal of minimizing the mass of the gearbox. The application of TO allows to obtain a better, lighter, and more efficient design of the gearbox by keeping its mechanical performance unchanged.