We propose a novel method to generate high-quality triangular meshes with specified anisotropy. Central to our algorithm is to present metric-adapted embeddings for converting the anisotropic meshing ...problem to an isotropic meshing problem with constant density. Moreover, the orientation of the input Riemannian metric forms a field, enabling us to use field-based meshing techniques to improve regularity and penalize obtuse angles. To achieve such metric-adapted embeddings, we use the cone singularities, which are generated to adapt to the input Riemannian metric. We demonstrate the feasibility and effectiveness of our method over various models. Compared to other state-of-the-art methods, our method achieves higher quality on all metrics in most models.
•A novel embedding-based method is proposed to generate high-quality triangular meshes with specified anisotropy.•Our embedding is metric-adapted to convert the anisotropic condition to an isotropic constraint with constant density.•The orientation of the input Riemannian metric is used to improve regularity and penalize obtuse angles.
This paper proposes a new equivalent magnetic network (EMN) model for vehicular dual-permanent-magnet vernier (DPMV) machines by applying a generalized modeling method. First, the magnetic circuit ...method and the meshing method are combined together to improve the modeling efficiency of the DPMV machine. The magnetic circuit method is used to generate conventional lumped parameter permeances to shorten time consumption, whereas the mesh method is utilized in disordered magnetic fields to obtain high precision. Second, a meshing solution for oblique region is proposed to enhance modeling flexibility. Moreover, the flux distributions in meshes are represented without magnetic field pre-delineation, which enables its utilization as a self-adaptive reluctance network model in design optimization. Finally, the proposed EMN model is used to predict the performance of the DPMV machine, considering leakage magnetic flux, local iron saturation, and magnetic field modulation effect simultaneously. Meanwhile, the effectiveness of the proposed EMN model is verified by comparison with finite-element analysis and experimental tests.
Analysis of friction and lubrication between meshing gear teeth with complicated tooth surfaces has been a difficult problem in analysis of meshing contact of gear real tooth surfaces. Traditional ...computational fluid dynamics (CFD) methods cannot precisely create a structured mesh for complicated space surface and thus have limited applicability for solving problems. In this study, the moving particle semi-implicit (MPS) method is proposed to find out impacts of ration speed, immersion depth, worm arrangement, viscosity of lubricant on the churning power losses and oil pressure distribution in a roller enveloping worm gear drive. The application of MPS method for the simulation of gear meshing and lubrication overcomes the difficulty of meshing gear tooth surfaces that maintain all complex structural details. Meanwhile, an experimental study is performed to verify the simulation results and validate the applied computational methods. The combined experimental and computational approach presented in this paper thus represents a solution for numerically analyzing the friction and lubrication between two moving curved surfaces and can be applied for solving a broad range of transmission problems.
•Use MPS method to study the effects of speed, oil depth, viscosity, and worm arrangement on lubrication of speed reducer.•Present a combined experimental-computational method to study lubrication and friction between two complicated surfaces.•Demonstrate advantages of meshfree methods over traditional mesh-based methods in simulation of incompressible flows.•Build a prototype for the high precision speed reducer based on a roller enveloping worm/worm gear system.
Laminated panels are widely used in various industries due to their distinct advantages. The design of laminated composites requires efficient methodologies due to the vast design space. This study ...proposes a new spectral element modeling approach for accurate and computationally efficient analysis of laminated composites with arbitrarily shaped cutouts. The method employs a coarse quad meshing approach and a spectral Chebyshev method to determine the element matrices. The presented method enables obtaining high-fidelity models by applying h- and p-refinements following a non-dimensional approach, aiming to yield a model with the fewest degrees of freedom to achieve a desired convergence level. Benefiting from the advantages of both meshless methods (in terms of computational efficiency) and finite element methods (in terms of geometric capabilities), we performed several case studies for laminated panels with cutouts and it is shown that the presented spectral element method (SEM) enables calculating the natural frequencies and the mode shapes as accurate as FEM, yet decreases the analysis duration by 13 folds. Furthermore, the developed approach was employed with a gradient-based optimizer or genetic algorithm to demonstrate the design of (sandwich) laminated composites for obtaining optimal lamination parameters and 2D Pareto fronts.
•A spectral element method (SEM) with a coarse quad meshing technique is presented.•It enables accurately predicting the dynamics of composite panels with cutouts.•Compared to FEA, the computational cost is significantly reduced.•The performance of the SEM is demonstrated via various case studies.
In this paper, the meshing stiffness of spur gear pairs, considering both global tooth deflections and local contact deflections, is evaluated at any point of the path of contact and approximated by ...an analytical, simple function. With this function, the load sharing ratio is calculated and compared with previous results obtained from the hypothesis of minimum elastic potential energy (MEPE model), considering the tooth deflections, but neglecting the hertzian deflections. Critical bending and contact stresses from both models are also compared both for standard and high contact ratio spur gears.
•Mesh stiffness equations including hertzian effects for spur gears are presented.•Approximate equations for the mesh stiffness and the load sharing ratio are provided.•Critical stresses and load conditions for bending and pitting are obtained.•Results from a model regardless contact deflections are compared.•Validation by Finite Element Analysis is performed.
Abstract
Based on the existing research on the conjugate curve gear, the meshing equation of the shaving process is deduced according to the gear meshing principle and the working principle of the ...disc shaving cutter, so as to obtain the tooth surface equation of the shaving cutter corresponding to the conjugate curve gear, which provides a theoretical basis for the design of the shaving cutter of the conjugate curve gear.
We develop a numerical assessment of the Virtual Element Method for the discretization of a diffusion–reaction model problem, for higher “polynomial” order k and three space dimensions. Although the ...main focus of the present study is to illustrate some h-convergence tests for different orders k, we also hint on other interesting aspects such as structured polyhedral Voronoi meshing, robustness in the presence of irregular grids, sensibility to the stabilization parameter and convergence with respect to the order k.
Helical gears are generally considered to be more stable than spur gears. But rattling of the helical gear transmission is found in the engineering practice. The torsional dynamics equations of ...helical gear pair in high-speed railway gearbox are established in order to reveal the rattling mechanism of helical gear transmission. Double and three teeth pair drive-side meshing are considered. The multi-state meshing zone, load distribution rate and time-varying stiffness determined by contact ratio are analyzed and calculated. The dynamic characteristic transition process of the system is analyzed according to the bifurcation diagrams and the corresponding top Lyapunov exponent (TLE) diagrams, phase portraits, Poincaré maps and time history spectrums of dynamic meshing force based on the calculation of these parameters. The tooth disengagement, tooth back-side contact and their parameter range are found. This study can provide theoretical basis for rattling suppression and transmission stability improvement of helical gear pair.
We introduce a new algorithm for generating tetrahedral meshes that conform to physical boundaries in volumetric domains consisting of multiple materials. The proposed method allows for an arbitrary ...number of materials, produces high-quality tetrahedral meshes with upper and lower bounds on dihedral angles, and guarantees geometric fidelity. Moreover, the method is combinatoric so its implementation enables rapid mesh construction. These meshes are structured in a way that also allows grading, to reduce element counts in regions of homogeneity. Additionally, we provide proofs showing that both element quality and geometric fidelity are bounded using this approach.
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