Search Results (4)

The application of ceramic particle-reinforced metal matrix composites (CPRMMCs) in the nuclear power sector is primarily dependent on their mechanical and thermal properties. A comprehensive understanding of the structure–property (SP) linkages between microstructures and macroscopic properties is critical for optimizing material properties. However, traditional studies on SP linkages generally rely on experimental methods, theoretical analysis, and numerical simulations, which are often associated with high time and economic costs. To address this challenge, this study proposes a novel method based on Materials Informatics (MI), combining the finite element method (FEM), graph Fourier transform, principal component analysis (PCA), and machine learning models to establish the SP linkages between the microstructure and thermodynamic properties of CPRMMCs. Specifically, FEM is used to model the microstructures of CPRMMCs with varying particle volume fractions and sizes, and their elastic modulus, thermal conductivity, and coefficient of thermal expansion are computed. Next, the statistical features of the microstructure are captured using graph Fourier transform based on two-point spatial correlations, and PCA is applied to reduce dimensionality and extract key features. Finally, a polynomial kernel support vector regression (Poly-SVR) model optimized by Bayesian methods is employed to establish the nonlinear relationship between the microstructure and thermodynamic properties. The results show that this method can effectively predict FEM results using only 5–6 microstructure features, with the R² values exceeding 0.91 for the prediction of thermodynamic properties. This study provides a promising approach for accelerating the innovation and design optimization of CPRMMCs. Full article

The lifetime cost evaluation of a seal must take into account all expenses throughout its operation. The thermodynamic aspects of mechanical face seals (MFSs) analyzed using FEM for various pairs of materials and their correlation with wear, reliability, and economic feasibility have not been researched in the literature. The MFSs analyzed in this paper were manufactured by ROSEAL S.A. for use in water pumps. The materials of the primary seal rings used by manufacturers were taken into account. The operating conditions were as follows: n = 3000 rpm, water temperature = 80 °C, and pressure = 0.1 MPa. In our study, we focused on the thermodynamic phenomena occurring in the MFS. The thermodynamic simulation was run using the FEM software MSC Nastran. Maps of the temperatures and the heat flow in the primary seal rings, for the two types of MFS and for different pairs of materials, were obtained using FEM analysis. The results highlight that the flow rate of leaks increases linearly with the angular speed of the pressure ring and is independent of the materials used in the primary seal. Full article

Considering the demand for low temperature bonding in 3D integration and packaging of microelectronic or micromechanical components, this paper presents the development and application of an innovative inductive heating system using micro coils for rapid Cu-Sn solid-liquid interdiffusion (SLID) bonding at chip-level. The design and optimization of the micro coil as well as the analysis of the heating process were carried out by means of finite element method (FEM). The micro coil is a composite material of an aluminum nitride (AlN) carrier substrate and embedded metallic coil conductors. The conductive coil geometry is generated by electroplating of 500 µm thick copper into the AlN carrier. By using the aforementioned micro coil for inductive Cu-Sn SLID bonding, a complete transformation into the thermodynamic stable ε-phase Cu₃Sn with an average shear strength of 45.1 N/mm² could be achieved in 130 s by applying a bond pressure of 3 MPa. In comparison to conventional bonding methods using conduction-based global heating, the presented inductive bonding approach is characterized by combining very high heating rates of about 180 K/s as well as localized heating and efficient cooling of the bond structures. In future, the technology will open new opportunities in the field of wafer-level bonding. Full article

Accurate comprehension of thermodynamic demeanor and pressure pulsation propagation is of great attractiveness in a reciprocating compressor system. To consider the reciprocal interaction between compressor and pipelines, a hybrid numerical model is thus built by coupling the in-cylinder lumped parameter approach, in-pipe 1D gas dynamics and 3D acoustic characteristics of chambers. The transmission and reflection coefficients of a geometrically complex chamber are achieved by the definition of an acoustic characterization method based on acoustic FEM simulation data, with a high level of accuracy. Numerical results of this new hybrid model are compared with predictions from the traditional hybrid model with in-pipe 1D gas dynamics, together with experimental data. Through comparison analysis, the advantages are highlighted in using the acoustic FEM characterization for complex elements since the new model performs numerical solution without introducing any simplifications to the geometry of fluid domain. Full article