Polyhedral Mesh To Solid NEW! Crack

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I created something in Rhino and imported it in Autocad as .3ds file but the geometry is not a solid one but a polyface mesh and I cannot edit it with boolean commands, thus I cannot continue editing it...

"Since version 2010 you can directly convert a "watertight" 3D mesh (polyface mesh) to a 3D solid. To keep the original unsmoothed facets, set the FACETERSMOOTHLEV variable to 0. Use the MESHSMOOTH command to convert the 3D mesh to a MESH object (if necessary) and then make the 3D solid from it using the CONVTOSOLID command (right-click on the mesh and choose "Convert mesh to")."

You might try Inventor Fusion - it's free but it expires next year sometime around April or May - it is a development product. Within it there is a way to thicken (I believe it will handle a mesh), creating a solid body.

or please let me if there is any other means to calculate or check or to change dimensions with in polymesh structure.i have triedconvtosolid command even surface commaad didnt work. error: cannot convert selected object.

However, suitable first-order shape functions were not available for element geometries with more than four sides until around the 1970s. Wachspress [2, 3] introduced a new type of shape functions based on principles of perspective geometry known as Wachspress shape functions. Linear relations within shape functions for elements with more than four nodes are obtained by using rational functions. It can be seen that the shape functions consist of complex rational functions, which requires special integration techniques to solve. Wachspress method was revisited and gained more attention around the year 2000. Meanwhile, various methods have been proposed over the years to form polygonal/polyhedral finite elements and to solve problems within polygonal/polyhedral meshes. These methods are as follows:(1)Voronoi cell finite element method (VCFEM) and polygonal finite element based on parametric variational principle and the parametric quadratic programming method(2)Hybrid polygonal element (HPE)(3)Conforming polygonal finite element method based on barycentric coordinates (conforming PFEM, or PFEM)(4)n-Sided polygonal smoothed finite element method (nSFEM)(5)Polygonal scaled boundary finite element method (PSBFEM)(6)Mimetic finite difference (MFD) and virtual element method (VEM)(7)Virtual node method (VNM)(8)Discontinuous Galerkin finite element method (DGFEM)(9)Trefftz/Hybrid Trefftz polygonal finite element (T-FEM or HT-FEM) and Boundary element based FEM (BEM-based FEM)(10)Hybrid stress-function (HS-F) polygonal element(11)Base forces element method (BFEM)(12)Other recent techniques/schemes

Another attempt to form polygonal finite element method can be seen within the smoothed finite element method (SFEM). SFEM is formed by merging conventional FEM with meshless methods. SFEM was initially formed for quadrilateral elements. Later, Dai, Liu, and Nguyen [70] extended the four-node quadrilateral smoothed elements to arbitrary sides termed as n-sided polygonal smoothed finite elements (nSFEM) and implemented the method in solid mechanics (macrolevel).

nCS-FEM has many advantages over the conventional FEM such as the fact that stability provides accurate results as compared to the conventional FEM. This is because the stiffness matrices of nCS-FEM tend to be less stiff and can be applied for nearly incompressible materials by using selective integration schemes to avoid volumetric locking phenomena [70]. However, for solid mechanics, nCS-FEM is proposed to be used only for regions near the boundary or very irregular parts. This is because use of these elements for interior regions would increase the number of nodes and eventually increases the computational cost [70]. Advantage of nNS-FEM is that it is immune from volumetric locking phenomena. Disadvantage of nNS-FEM is that the computational time is longer compared to conventional FEM for the same number of global nodes, due to larger bandwidth of stiffness matrices. Disadvantage of nES-FEM is that there is a tendency to overestimate or underestimate the strain energy of the model for some cases. Apart from that, similarly to nNS-FEM, nES-FEM requires more computational time compared to conventional 3-node triangular elements due to the larger bandwidth [72]. Comparison between the three types of nSFEM is provided by Nguyen et al. [72], for solid mechanics problem. It is shown that nES-FEM provides most accurate solution compared to the others and the stiffness/softness of the model of nES-FEM is in between the other two techniques. Combination of nES-FEM and nNS-FEM (termed as nES/NS-FEM) to avoid volumetric locking and to achieve faster convergence can be seen in the literature [72, 75]. Applications of nSFEM can be seen in determination of upper bound solutions to solid mechanics problems [73], fluid-solid interaction problems [75], and new application in analysis of elastic solids subjected to torsion [76]. Recently, nSFEM has been implemented for the analysis of fluid-solid interaction (FSI) problems in viscous incompressible flows together with sliding mesh [77]. Simulation results showed that the method performs better compared to the conventional finite elements. Major advantage of the nSFEM in FSI is that it is capable of performing independent domain discretization.

The method is advantageous compared to compatible PFEM due to the simple polynomial shape functions (which is easier to work with). VNM is found to be efficient in adaptive computation, by using quadtree or octree mesh. The method has been extended to 3D polyhedral (VPHE) and hexahedral forms and implemented in adaptive computations as can be seen in the literature [123, 125, 126]. Recently, the method has been coupled with extended FEM (XFEM) [127, 128].

Other recent techniques/methods include analysis of polygonal carbon nanotubes reinforced composite plates by using the first-order shear deformation theory (FSDT) and the element-free IMLS-Ritz method [174], an adaptive polygonal finite element method using the techniques of cut-cell and quadtree refinement [175], new adaptive mesh generation for polygonal element [176], and ultraweak formulations for high-order polygonal finite element methods [177]. New technique for 3-dimensional polyhedral elements can be seen within the framework of the finite volume method [178]. Another new approach to form polyhedral elements is by cutting a regular hexahedral element with CAD surfaces [179].

It is seen that currently there are few commercial software packages which are available for polygonal/polyhedral finite elements. However, software packages for other methods can be easily developed by incorporating the source codes developed by the researchers mentioned above with the available commercial polygonal mesh generators. Some of the software packages for polygonal/polyhedral mesh generation are Platypus (MATLAB based code) [187], ReALE [188], PolyMesher [189], PolyTop [190], OpenMesh [191], and more, which can be found in [192].

It can be seen that various finite elements have been proposed for engineering analysis. These elements have been proposed to facilitate meshing of the problem domain, to facilitate the analysis of physical phenomena, and to overcome drawbacks or limitations in the existing methods. This review enables the readers to identify advantages, disadvantages, and a comparison between the various techniques used in formation of polygonal/polyhedral finite elements.

Another approach to constructing polyhedral elements is to utilize SBFEM. In mid-1990s, SBFEM also known as the consistent infinitesimal finite-element-cell method was bought up by Wolf and Song as an extension to FEM to simulate the wave propagation in the unbounded domain30,31,32,33. As a similarity-based semi-analytical numerical approach for PDE, SBFEM has many advantages over the traditional FEM and Boundary Element Method (BEM) exhibiting high accuracy and flexibility34,35. SBFEM just needs boundary discretization reducing the problem spatial dimension by one with no need for a fundamental solution and the solution along the radial direction is in a precise closed-form. For the unbounded media, SBFEM can perfectly satisfy the boundary condition of the radiation damping. The unit-impulse response matrix in the time domain and the dynamic-stiffness matrix in the frequency domain of the unbounded media can be directly obtained, which is equivalent to a time and space coupling artificial non-reflecting boundary36. For the bounded media, the SBFEM is derived in a wedge media. The wedge media can be assembled into an arbitrary convex polyhedron (3D) or polygon (2D) super element revolving around the similarity center. If this assembly is not occlusive and the crack tip is positioned in the similarity center, the singularity of the field function can be directly described by the analytical solution along the radical crack surface. This superiority of mesh adaptability can be combined with the automatic mesh generation technique based on polyhedron elements.

The first try was a SBFEM formulation for arbitrary polyhedral elements and a simple method to generate polyhedral meshes based on octree presented by Talebi et al.37. To automatically generate an octree polyhedral mesh from the Standard Tessellation Language (STL) widely used in the 3D printing and Computer Aided Design (CAD), Liu et al.38 came up with a two-steps method. The first step is to generate an octree mesh within the domain enclosed by the surface defined in the STL. The second step is to cut the polyhedral elements with the surface. After the refinement of the second step, the poor boundary accuracy of the octree mesh is improved. Furthermore, Zhang et al.39 applied the SBFEM polyhedral elements to the non-matching meshes by adding nodes to the elements adjacent to the interface. By now, there is a slight limitation when using SBFEM polyhedral elements. Since the boundary is discretized by FEM elements, the facets of a polyhedral element must be a triangle or quadrilateral, which may lead to a facet division process. To resolve this limitation of SBFEM, Ooi et al.40 derived a dual SBFEM formulation over arbitrary faceted star convex polyhedron. On the other hand, Zou et al.41 brought up a FEM polyhedral element formulation with shape functions derived from SBFEM circumventing this limitation as well. The automatic polyhedral element based on SBFEM was applied to dynamic nonlinear analysis of hydraulic engineering42, concrete fracture modelling43, damage modelling44,45, Soil-Structure Interaction (SSI) analysis of NPP46, etc. These applications of SBFEM polyhedral meshes were mostly implemented by self-developed programs. Few of them integrate the SBFEM into the universal FEM software such as ABAQUS43,47. And these integrations is suitable for traditional FEM elements with fixed topologies only. The integration of SBFEM and the universal FEM software can promote each other. Implementation of arbitrary polyhedral elements in ABAQUS is still in need. 2b1af7f3a8