Complex Mesh Research Articles

AI‐Based Segmentation for Corrosion Risk Prediction in Carline Designs

ABSTRACTWith shortening development cycles, digital development rises in importance. Therefore, we present an approach to segment digital carlines based on their corrosion risk using digital data sets. A typical carline is described via STL‐Files that accumulate to approximately 25 million triangles. While physics‐based simulation models exist capable of predicting the onset of corrosion in local geometry settings, an application to a complex surface mesh would be prohibitively expensive to compute. This calls for data reduction techniques that reduce the number of triangles by identifying areas prone to corrosion, as well as those that are protected by measures such as adhesives. Therefore, the implementation of corrosion‐prone areas of a body‐in‐white part, as presented in Waibel et al., is extended by implementing a design measure segmentation for adhesive pipes. This work introduces a method to predict corrosion‐protected areas for flanges with adhesives by implementing a feature extraction and a transfer learning‐based workflow for data‐efficient training. The results of the implementation are the validated prediction on body‐in‐white parts with high precision.

Laparoscopic-Assisted, Percutaneous Cryoablation: A Novel Technique for the Treatment of Abdominal Wall Soft Tissue Tumors.

Percutaneous cryoablation is a first-line therapeutic option for primary neoplasms and metastatic lesions of the musculoskeletal system. Treatment of abdominal wall tumors is challenging as surgical resection can be highly morbid and necessitate complex reconstructive surgery; the efficacy of cryoablation for abdominal wall tumors may be limited by inadequate posterior margins owing to the proximity of intra-abdominal organs. With laparoscopy and insufflation, peritoneal structures can be safely mobilized away from the abdominal wall, allowing for adequate deep margin freeze and visualization of the ice ball. We present two patients with abdominal wall soft tissue tumors treated with a novel approach of laparoscopic-assisted, percutaneous ultrasound-guided cryoablation. Patient 1 is a 65-year-old female with metastatic extraskeletal myxoid chondrosarcoma, stable on systemic therapy, who presented with a new soft tissue metastasis to the abdominal wall. Resection would have necessitated a highly morbid complex abdominal wall reconstruction with mesh. Patient 2 is a 35-year-old female with a large abdominal wall desmoid tumor, diagnosed after miscarriage. Resection was relatively contraindicated owing to the morbidity of a complex abdominal wall reconstruction and concerns regarding potential future pregnancies after surgery. Both patients underwent procedures in the outpatient setting after discussion at multidisciplinary sarcoma tumor board. Laparoscopic enterolysis was performed to mobilize the bowel away from the abdominal wall, to allow direct visualization of the peritoneal aspect of the tumor, and to confirm adequacy of the posterior margin freeze of the lesion. Laparoscopic transversus abdominus preperitoneal (TAPP) blocks with local anesthetic were performed for postoperative pain control. Interventional radiology performed an ultrasound-guided cryoablation consisting of two freeze and thaw cycles. Both patients recovered well without complications and were without radiographic evidence of persistent or recurrent disease at 12 and 18 months postoperatively, respectively. We report a novel approach of laparoscopic-assisted cryoablation for the treatment of abdominal wall soft tissue tumors. This allowed for successful minimally invasive local control of these large tumors that would have otherwise required highly morbid resections with complex abdominal wall reconstruction and mesh repair.

Novel synthesis of 1-D silicon nanowires grown on pyramidal black silicon substrates and intense visible emission

This work shows a new way to grow 1-D Silicon Nanowires (SiNWs) over pyramidal black silicon used as substrates. These nanostructures are grown by the plasma-assisted vapor–liquid-solid (VLS) as a bottom-up process, using tin thin films as a catalytic metal and dichlorosilane gas as a silicon precursor. SiNWs were obtained with diameters from 300-600 nm and 4–6 µm lengths on the black silicon surface. Due to the pyramid-shaped and porous nature of the black silicon surface, SiNWs form a complex mesh nanostructure. This network has a large surface area and exhibits intense and effective photoluminescence with a peak in the green spectrum, which is attributed to the quantum confinement effect that occurred in small nc-Si embedded inside SiNWs. These structural configurations hold significant promise for applications in optical biosensors, solar cells, and other prospective fields.

EasySkinning: Target-oriented skinning by mesh contraction and curve editing

Skinning, a critical process in animation that defines how bones influence the vertices of a 3D character model, significantly impacts the visual effect in animation production. Traditional methods are time-intensive and skill-dependent, whereas automatic techniques lack in flexibility and quality. Our research introduces EasySkinning, a user-friendly system applicable to complex meshes. This method comprises three key components: rigid weight initialization through Voronoi contraction, precise weight editing via curve tools, and smooth weight solving for reconstructing target deformations. EasySkinning begins by contracting the input mesh inwards to the skeletal bones, which improves vertex-to-bone mappings, particularly in intricate mesh areas. We also design intuitive curve-editing tools, allowing users to define more precise bone influential regions. The final stage employs advanced deformation algorithms for smooth weight solving, crucial for achieving desired animations. Through extensive experiments, we demonstrate that EasySkinning not only simplifies the creation of high-quality skinning weights but also consistently outperforms existing automatic and interactive skinning methods.

Monte Carlo Source Convergence Diagnosis Method and Thermal-Physics Coupling Method Based on Functional Expansion Tallies

In iterative Monte Carlo calculations for nuclear reactors, the inactive cycles should be calculated first to ensure that the source distribution is converged, and then the tallies of various parameters in the active cycles can begin. In order to acquire the mesh-free distribution of the fission source, this research proposes the functional expansion tallies (FET) source convergence diagnosis method in the Reactor Monte Carlo code, which is a self-developed stochastic simulation code maintained by the Reactor Engineering Analysis Laboratory of Tsinghua University. Due to the randomness in Monte Carlo calculations and the difficulty in determining the precise source convergence, this paper proposes a diagnostic tool based on function curve similarity and moving average, and proposes an online real-time source convergence diagnosis method. The FET online source convergence method can terminate the calculation of the inactive cycle in real time according to the convergence diagnostic tool; thus it can greatly decrease the calculation time. The precise and effective transfer of data between different meshes is a difficult issue of thermal and physical coupling. Converting two separate meshes and transferring the data are exceptionally difficult and complex tasks within the conventional nuclear thermal-physics coupling approach. By applying the FET method to nuclear thermal-physics coupling, the mesh-free continuous-space fission source distribution can be obtained, which is suitable for more complex meshes. Additionally, computational memory can be minimized by replacing (transforming) the data from numerous mesh power distribution data points with the coefficients of the function.

Hybrid meshless-FEM method for 3-D magnetotelluric modelling using non-conformal discretization

SUMMARY We propose a novel method for 3-D magnetotelluric (MT) forward modelling based on hybrid meshless and finite-element (FE) methods. This method divides the earth model into a central computational region and an expansion one. For the central region, we adopt scatter points to discretize the model, which can flexibly and accurately characterize the complex structures without generating unstructured mesh. The meshless method using compact support radial basis function is applied to simulate this area's electromagnetic field. While in the expansion region, to avoid the heavy time consumption and numerical error of the meshless method caused by non-uniform nodes, we adopt a node-based finite-element method with regular hexahedral mesh for stability. Finally, the two discretized systems are coupled at the interface nodes according to the continuity conditions of vector and scalar potentials. Considering that the normal electric field is discontinuous at the interface with resistivity discontinuity, while the shape functions for the meshless method are continuous, we further adopt the visibility criterion in constructing the support region. Numerical experiments on typical models show that using the same degree of freedom, the hybrid meshless-finite element method (FEM) algorithm has higher accuracy than the node-based FEM and meshless method. In addition, the electric field discontinuity at interfaces is well preserved, which proves the effectiveness of the visibility criterion method. In general, compared to the conventional grid-based method, this new approach does not need the complex mesh generation for complex structures and can achieve high accuracy, thus it has the potential to become a powerful 3-D MT forward modelling technique.

Research and Application on High Precision Measurement Method of Large Mesh Antenna Surface

Abstract The development process of large mesh antennas requires a significant investment of time and resources for iterative measurements and adjustments to achieve high precision in the large mesh reflector. In this paper, a novel measurement method for the precision of large mesh antenna surfaces is proposed to reduce the development process. Multiple measurement cameras have been utilized to set up a network system, enabling data integration for comprehensive analysis and computational calculations. In this approach, the implementation of a one-click and the rapid measurement function represent substantial advancements. The single measurement time has been successfully reduced from 40 minutes to 2 minutes, which addresses the challenge of high efficiency and precision measurement application on the complex mesh antenna surface. Then the optimization of calibration is accomplished through the meticulous measurement of network patterns, marker points, and reference bars to improve the precision accuracy on the foundation of rapid measurements, combined with the simulation analysis. The final results have been practically verified and successfully applied to model development, which provides a crucial reference for subsequent endeavors involving the rapid and automated measurement of similar antennas.

Coupling a nonlinear finite element mooring model with an overset CFD solver for dynamic analysis of floating structures in waves

An accurate prediction of motion responses of a moored floating structure requires high-fidelity coupled analysis between the structure and its mooring system in waves, which involves both mooring line dynamics and fluid dynamics. In this paper, we develop a nonlinear finite element dynamic mooring analysis module that allows large axial stretching of mooring lines under the open source CFD framework OpenFOAM, and couple it with an Overset CFD solver to establish a fully coupled finite element mooring-CFD analysis model for floating structures. The coupled model is advantageous over existing models in that it is able to deal with large axial mooring stretching and complex mesh motions induced by significant structure responses under severe operating conditions. The developed dynamic mooring analysis method is firstly validated against publicly available data. In order to validate the coupled model, a series of experimental tests were carried out for a semi-submersible platform moored by eight catenary lines under different operating conditions, including free decay, regular and irregular wave tests. The dynamic responses of the floating structure and mooring tension are analyzed and compared with experimental data. Results show that numerically predicted structure responses and mooring tension are generally in good agreement with experimental measurements. Meanwhile, the strongly nonlinear large-amplitude resonant motions generated by the interaction of irregular waves with the moored floating structure are also investigated. Comparisons reveal that the coupled model can accurately predict the resonant spectral peaks of the structure responses, indicating that the it is capable of simulating large-amplitude motions of moored floating structures. The coupled model developed in this paper can be further applied to study the survivability of moored floating structures under harsh sea conditions.

Carbon Emissions in Cloud Computing: Challenges and Opportunities for Sustainability

In the land of the unreal cloud computing, where bits go on unseen routes, the grim truth manifests itself to the abundant marvels in among the virtuals; carbon emissions. The following concerns the novel problem of greenhouse gas collection within cloud computing - it finds the most hidden source of pollution and building blocks behind this digital paradox. From the humming data centers, crammed with complex meshes of hardware and processes drawing massive amounts of energy, and the kaleidoscope of sources power these huge fiends, an actual stage is created to allow emissions to appear on it in silence. And in the midst of this complexity, even if we do not see very clearly where we are heading towards solutions, there is some light, making us capable for what comes. Source is the right word. The alchemist of innovation, from the energy saving squeezing to the resource sharing singing, all found the soil. Transparency thus turns out to be a steering light amid the obscurity and leads stakeholders towards the trajectories of greener spheres as carbon accounting frameworks show the way. Coordination pivots to the focal point linking stakeholders in the sector as well as the policy and advocacy networks. This weft and waft forms a device that corresponds to the structure of collective action. Hence, beneath the infinitude of the cloud, the two play a dance together where the advanced technology and environmental preservation work together to pave the way of a future that celebrates resilience and sustainability.

Gamma Irradiation Effect on Polymeric Chains of Epoxy Adhesive.

The study of materials for space exploration is one of the most interesting targets of international space agencies. An essential tool for realizing light junctions is epoxy adhesive (EA), which provides an elastic and robust material with a complex mesh of polymeric chains and crosslinks. In this work, a study of the structural and chemical modification of a commercial two-part flexible EA (3M™ Scotch-Weld™ EC-2216 B/A Gray), induced by 60Co gamma radiation, is presented. Combining different spectroscopic techniques, such as the spectroscopic Fourier transform infrared spectroscopy (FTIR), the THz time-domain spectroscopy (TDS), and the electron paramagnetic resonance (EPR), a characterization of the EA response in different regions of the electromagnetic spectrum is performed, providing valuable information about the structural and chemical properties of the polymers before and after irradiation. A simultaneous dissociation of polymeric chain and crosslinking formation is observed.The polymer is not subject to structural modification at an absorbed dose of 10 kGy, in which only transient free radicals are observed. Differently, between 100 and 500 kGy, a gradual chemical degradation of the samples is observed together with a broad and long-living EPR signal appearance. This study also provides a microscopic characterization of the material useful for the mechanism evaluation of system degradation.

An efficient localized Trefftz method for the simulation of two-dimensional sloshing behaviors

This study proposes a new method for effectively and accurately simulating sloshing in a two-dimensional numerical tank. This technique uses the localized Trefftz method (LTM), a meshless numerical approach. Sloshing in a numerical tank is mathematically described as a space-time boundary-value problem rooted in potential flow theory. This occurrence is governed by a second-order partial differential equation and two nonlinear free-surface boundary conditions. In this study, the moving boundary problem undergoes discretization in time and space by using the LTM and the explicit Euler method, respectively. After discretization with the explicit Euler method, the elevation of the free surface is updated, and a boundary-value problem is generated at each time step. This boundary-value problem can be effectively examined using the recently developed LTM, which eliminates the need for complex meshing. Contrary to conventional methods, such as the method of fundamental solutions and the boundary element method, the LTM generates sparse matrices, allowing large-scale numerical simulations. Four numerical examples are presented to demonstrate the clarity and accuracy of the proposed meshless approach.

The effects of assistance dogs on social acknowledgements and engagement of people with visible disabilities – A case study

Abstract Stigmatization of people with visible disabilities is a well-recognized concept, as is the knowledge that Assistance Dogs (ADs) may serve as social lubricants. This case study explored the interplay of these two concepts in the everyday life of a person (Mary) with a visible disability and her AD (Cino). This mixed methods study collected both quantitative observational data and qualitative interview data. Four episodes of Mary interacting in the community with and without Cino (AD) were observed using an observation checklist. These were complimented by four in-depth interviews with Mary and one with a close family member. Interview transcripts were used to construct a thematic understanding of the complex ways in which Mary’s life and experience of living with significant disability are impacted by having Cino to support her. Observational data identified that the presence of Mary’s AD considerably increased social acknowledgements of Mary from members of the public during community interactions. Two major themes (The dog makes a difference, and Lack of understanding, awareness, and support) each with four subthemes, emerged from the interviews. The complex mesh of experiences related to the support of her AD(s), both positive and negative, are mapped in the subthemes. While both positive and negative aspects of AD ownership were identified and explored, Mary assesses the net effect of having Cino, as ultimately positive, outweighing numerous complications and drawbacks in life lived with disability. The findings contribute to a more nuanced understanding of the way ADs can impact both positively and negatively in the lives of people living with disability. These insights provide points that can be used in discussing potential AD support with people exploring this option. They also caution against simplistic, “do ADs really work?” approaches in research as Mary’s lived experiences show that this is nuanced by multiple personal, clinical, social, physical, and broad environmental factors.

The Monte Carlo Thermal-Physics Coupling Method Based on Functional Expansion Tallies

In the Monte Carlo thermal-physical calculations for nuclear reactors, the precise and effective transfer of data between different meshes is a difficult issue of thermal and physical coupling. Converting two separate meshes and transferring the data is an exceptionally difficult and complex task within the conventional nuclear thermal-physics coupling approach. The newly developed Functional Expansion Tallies (FET) method can obtain the continuous distribution of parameters in the solution space. By applying FET method to nuclear thermal-physics coupling, the no-mesh continuous fission energy distribution can be obtained, which is suitable for more complex meshes. Additionally, the computational memory can be minimized by substituting the data from numerous mesh power distribution data points with the coefficients of the function.

Electrical Performance Analysis and Prediction for Complex Mesh Based on Model Angles

Electrical Performance Analysis and Prediction for Complex Mesh Based on Model Angles

LATTICE BOLTZMANN ANALYSIS OF MIXED CONVECTION IN A LID-DRIVEN CAVITY WITH AN INNER HOT ELLIPTICAL BLOCK: EFFECT OF BLOCK INCLINATION

This study is a computational analysis of hydrodynamic and thermal behavior of combined natural and forced convection with a moving wall in a square enclosure containing an elliptical block. This inner block is exposed to a hot temperature. The enclosure is full of air which is cooled on its side walls by a low temperature. The remaining surfaces are thermally insulated, and the upper surface is sliding at a steady speed <i>u</i><sub>0</sub>. In particular, the impact of various factors related to geometry, such as the emplacement and the elliptical block inclination are analyzed for the range of the dimensionless parameter Richardson number (0.01 ≤ Ri ≤ 100) by using lattice Boltzmann method (LBM) with single relaxation time model (SRT). LBM offers the advantage of handling irregular geometries and curved boundaries without requiring complex mesh generation, simplifying computations, and reducing computational costs in comparison to the traditional methods. The findings are in the forms of streamlines, temperature contours, the mean Nusselt number, and the fluid mean temperature inside the enclosure. The results show that for the prevailing natural convection and for the centrally placed elliptical block, the dynamic and thermal fields are almost indicated by symmetry with regard to the mid-vertical of the enclosure. Moreover, the inclination of the elliptical block prevents the enhancement of the heat transfer for all positions of the block; except when the block is located close to the upper surface, the inclination improves the rate of heat transfer especially for Ri ≤ 1.

Unique laboratory “Currents in the ground”

A brief description of the scientific laboratory is given, which has become a flagship in the field of electrical energy, which made it possible to obtain unique results on grounding and electrical safety, which were included in state regulatory documents. It is shown that a well-known scientific school has been created in the laboratory for the study of processes in grounding devices of electrical installations. The laboratory was founded in 1971 and has not been described previously. The article shows the main building in the form of a two-story building and a nearby stack-type pulse voltage generator for a voltage of 1,250,000 V. The circuit allows for reconnecting capacitors on floors to obtain different capacitances in the discharge. To connect to the grounding device under study, a portable overhead line with split wires is used. A map of grounding fields on the laboratory territory is provided. This allows you to design almost any design of a grounding device. Fields of vertical and horizontal grounding conductors of various lengths are used; fields of complex mesh grounding conductors; groups of single vertical electrodes of different lengths. The laboratory has several sets of self-powered electronic high-speed oscilloscopes, shielded and isolated from ground to avoid interference. The range of research questions can be significantly expanded by using already installed objects: an experimental overhead line with a voltage of 220 kV on nine reinforced concrete supports; cable line 600m long; a dynamic and thermal test stand, equipped with a circuit for obtaining industrial frequency currents of up to 4 kA at a voltage of 0.4 kV; 120 linear meters of reinforced concrete trays were laid on the field of a complex mesh grounding device for laying communication and control cables in them; two additional pulse voltage generators 1,600,000 V and 1,000,000 V (the latter allows transportation to full-scale test sites outside the laboratory); test transformers IOM-100/100.

Radial Basis Functions Approximation Method for Time-Fractional FitzHugh–Nagumo Equation

In this paper, a numerical approach employing radial basis functions has been applied to solve time-fractional FitzHugh–Nagumo equation. Spatial approximation is achieved by combining radial basis functions with the collocation method, while temporal discretization is accomplished using a finite difference scheme. To evaluate the effectiveness of this method, we first conduct an eigenvalue stability analysis and then validate the results with numerical examples, varying the shape parameter c of the radial basis functions. Notably, this method offers the advantage of being mesh-free, which reduces computational overhead and eliminates the need for complex mesh generation processes. To assess the method’s performance, we subject it to examples. The simulated results demonstrate a high level of agreement with exact solutions and previous research. The accuracy and efficiency of this method are evaluated using discrete error norms, including L2, L∞, and Lrms.

A conic programming approach to the wrinkling of pneumatic membranes using convex potentials

This paper presents a novel conic programming approach for modeling the wrinkling of isotropic hyperelastic membranes subject to nonlinear loading and finite strains, employing convex potentials derived from tension field theory. The incompressible neo-Hookean strain energy is recast as a minimization problem over a set of cones, with a semidefinite constraint on the deformed surface metric. To address pneumatic membranes, a linearized volumetric potential is introduced, reestablishing convexity for follower forces, and Boyle's law is expressed as a minimization problem over the exponential cone.The primal–dual interior point method solves the total potential energy minimization problem, with convergence verified using the analytical solution of a sheared planar membrane. The proposed model, applied to examples of increasing complexity, reveals intriguing membrane behaviors rarely discussed in existing literature. The method is shown to be robust, even when handling highly wrinkled membranes, which are challenging to address using direct nonlinear equilibrium analysis or nonlinear interior point methods.Implementation using high-level automatic code generation tools (FEniCS) results in concise, extensible code. The findings point to several avenues for future research, such as exploring complex material models, mesh refinement, dynamics, and parametric design. Additionally, the linearization process implies potential applicability of the methods to nonlinear problems beyond membrane mechanics.

Brazilian splitting experiment and finite element simulation analysis of the influence of bedding loading angle on shale fracture mode

During the diagenetic processes of compaction and cementation, shale forms multiple beddings, significantly effecting the rock anisotropy. Therefore, it is important to study the effect of bedding on the mechanical properties of shale to guide fracturing engineering. To study the failure mode and fracture morphology of shale with bedding planes under different bedding dip angles, Brazilian disc splitting tests and finite element numerical simulations are performed for shale samples and the results are compared. (1) The bedding angle has a significant effect on the failure mode and tensile strength of shale, and the tensile strength tends to increase with increasing bedding angle. (2) The failure modes of shale under different bedding dip angles can be divided into three types: tensile failure along the bedding plane; comprehensive shear and tensile failure of the matrix and the bedding plane; and matrix tensile failure. (3) The direction of secondary cracks is mostly perpendicular to the bedding plane, and a smaller angle between the load application direction and the bedding direction results in a larger number of generated cracks with more complex shapes. (4) When the loading angle of the bedding is 30°, the tensile strength is low and the matrix and the bedding plane are comprehensively destroyed by shear and tension, resulting in a more complex joint mesh; conversely, when the bedding angle is greater than 60°, the tensile strength increases and the complexity of the seam mesh decreases. These findings can provide guidance for the selection of the bedding angle and the design of fracturing schemes in fracturing engineering.

Efficient inverse-designed structural infill for complex engineering structures

Inverse design of high-resolution and fine-detailed 3D lightweight mechanical structures is notoriously expensive due to the need for vast computational resources and the use of very fine-scaled complex meshes. Furthermore, in designing for additive manufacturing, infill is often neglected as a component of the optimized structure. In this paper, both concerns are addressed using a so-called de-homogenization topology optimization procedure on complex engineering structures discretized by 3D unstructured hexahedrals.Using a rectangular-hole microstructure (reminiscent to the stiffness optimal orthogonal rank-3 multi-scale) as a base material for the multi-scale optimization, a coarse-scale optimized geometry can be obtained using homogenization-based topology optimization. Due to the microstructure periodicity, this coarse-scale geometry can be up-sampled to a fine single-scale physical geometry with optimized infill, with only a minor loss in structural performance and at a fraction of the cost of a fine-scale solution. The upsampling on 3D unstructured grids is achieved through stream surface tracing, aligning with the optimized local orientations. The periodicity of the physical geometry can be tuned, such that the material serves as a structural component and also as an efficient infill for additive manufacturing designs.The method is demonstrated through three examples of varying geometrical complexity. It achieves comparable structural performance to “brute force” state-of-the-art methods but stands out for its significant computational time reduction. By allowing multiple active layers, the mapped solution becomes more mechanically stable, leading to an increased critical buckling load factor without additional computational expense. The control of active layers also provides direct control over the internal structure, i.e., infill, ensuring that the infill is incorporated as a structural component and enhancing the manufacturability of the de-homogenization procedure. Furthermore, the proposed approach exhibits promising results, achieving volume fractions and weighted compliance values within 5% of the large-scale SIMP model, while demonstrating a computational efficiency improvement ranging from 10 times to over 250 times.