scholarly journals WingMesh: A Matlab-Based Application for Finite Element Modeling of Insect Wings

Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 546
Author(s):  
Shahab Eshghi ◽  
Vahid Nooraeefar ◽  
Abolfazl Darvizeh ◽  
Stanislav N. Gorb ◽  
Hamed Rajabi
Keyword(s):  
Finite Element ◽  
Numerical Techniques ◽  
Arbitrary Domain ◽  
Physical Sciences ◽  
Complex Objects ◽  
Fe Method ◽  
Insect Wings ◽  
The Earth ◽  
Out Of Plane ◽  
Burning Algorithm

The finite element (FE) method is one of the most widely used numerical techniques for the simulation of the mechanical behavior of engineering and biological objects. Although very efficient, the use of the FE method relies on the development of accurate models of the objects under consideration. The development of detailed FE models of often complex-shaped objects, however, can be a time-consuming and error-prone procedure in practice. Hence, many researchers aim to reach a compromise between the simplicity and accuracy of their developed models. In this study, we adapted Distmesh2D, a popular meshing tool, to develop a powerful application for the modeling of geometrically complex objects, such as insect wings. The use of the burning algorithm (BA) in digital image processing (DIP) enabled our method to automatically detect an arbitrary domain and its subdomains in a given image. This algorithm, in combination with the mesh generator Distmesh2D, was used to develop detailed FE models of both planar and out-of-plane (i.e., three-dimensionally corrugated) domains containing discontinuities and consisting of numerous subdomains. To easily implement the method, we developed an application using the Matlab App Designer. This application, called WingMesh, was particularly designed and applied for rapid numerical modeling of complicated insect wings but is also applicable for modeling purposes in the earth, engineering, mathematical, and physical sciences.

Finite-element EM modelling on hexahedral grids with an FD solver as a pre-conditioner

2020 ◽  
Vol 223 (2) ◽  
pp. 840-850
Author(s):  
Nikolay Yavich ◽  
Michael S Zhdanov
Keyword(s):  
Finite Element ◽  
Linear Equations ◽  
The Black Sea ◽  
Iterative Solver ◽  
System Of Linear Equations ◽  
Numerical Techniques ◽  
Fe Modelling ◽  
Fe Method ◽  
Rectangular Grids ◽  
Smoothing Procedure

SUMMARY The finite-element (FE) method is one of the most powerful numerical techniques for modelling 3-D electromagnetic fields. At the same time, there still exists the problem of efficient and economical solution of the respective system of FE equations in the frequency domain. In this paper, we concentrate on modelling with adapted hexahedral or logically rectangular grids. These grids are easy to generate, yet they are flexible enough to incorporate real topography and seismic horizons. The goal of this work is to show how a finite-difference (FD) solver can be used as a pre-conditioner for hexahedral FE modelling. Applying the lowest order Nédélec elements, we present a novel pre-conditioned iterative solver for the arising system of linear equations that combines an FD solver and simple smoothing procedure. The particular FD solver that we use relies on the implicit factorization of the horizontally layered earth matrix. We assessed runtime and accuracy of the presented approach on synthetic and real resistivity models (topography of the Black Sea continental slope). We further compared performance of our program versus publicly available Mare2DEM, ModEM and MUMPS programs/libraries. Our examples involve plane-wave and controlled source modelling. The numerical examples demonstrate that the presented approach is fast and robust for models with moderate contrast, supports highly deformed cells, and is quite memory-economical.

scholarly journals Out-of-plane local mechanism analysis with finite element method

2021 ◽  
Vol 8 (1) ◽  
pp. 130-136
Author(s):  
Roberto Spagnuolo
Keyword(s):  
Finite Element ◽  
Masonry Walls ◽  
Finite Element Models ◽  
Mechanism Analysis ◽  
Fem Method ◽  
Local Mechanism ◽  
Out Of Plane ◽  
Smeared Crack ◽  
The Stability ◽  
No Tension Material

Abstract The stability check of masonry structures is a debated problem in Italy that poses serious problems for its extensive use. Indeed, the danger of out of plane collapse of masonry walls, which is one of the more challenging to evaluate, is traditionally addressed not using finite element models (FEM). The power of FEM is not properly used and some simplified method are preferred. In this paper the use of the thrust surface is suggested. This concept allows to to evaluate the eccentricity of the membrane stresses using the FEM method. For this purpose a sophisticated, layered, finite element with a no-tension material is used. To model a no-tension material we used the smeared crack method as it is not mesh-dependent and it is well known since the early ’80 in an ASCE Report [1]. The described element has been implemented by the author in the program Nòlian by Softing.

Efficient Fatigue Testing of Tubular Joints

2015 ◽  
Author(s):  
P. Thibaux ◽  
J. Van Wittenberghe ◽  
E. Van Pottelberg ◽  
M. Van Poucke ◽  
P. De Baets ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Testing ◽  
Fatigue Loading ◽  
Tubular Joints ◽  
Testing Method ◽  
Out Of Plane ◽  
Resonance Principle ◽  
Tubular Joint ◽  
The Cost ◽  
Good Agreement

Tubular joints are intensively used in off-shore structures for shallow waters. Depending on the sea conditions and the type of structure, the design can be fatigue driven. This is particularly the case for off-shore wind turbines, where turbulences are generating a fatigue loading. Any improvement of the fatigue performance of the tubular joint would be beneficial to reduce the weight and the cost of the structure. To assess efficiently the fatigue resistance of the tubular joint, a testing method has been developed based on the resonance principle. The complete circumference of the welded joint can be loaded, successively in the in-plane and out-of-plane modes at a frequency close to 20Hz. Finite element computations were used to investigate the feasibility of the concept. Then, an X-node was made and successfully tested to investigate the stress distribution along the weld. The experimental results were compared with finite element computations, giving a good agreement.

scholarly journals Out-of-Plane Vibration of Curved Uniform and Tapered Beams with Additional Mass

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Hamdi Alper Özyiğit ◽  
Mehmet Yetmez ◽  
Utku Uzun
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Natural Frequencies ◽  
Variable Cross ◽  
Additional Mass ◽  
Inertia Effects ◽  
Tapered Beam ◽  
Out Of Plane ◽  
Good Agreement

As there is a gap in literature about out-of-plane vibrations of curved and variable cross-sectioned beams, the aim of this study is to analyze the free out-of-plane vibrations of curved beams which are symmetrically and nonsymmetrically tapered. Out-of-plane free vibration of curved uniform and tapered beams with additional mass is also investigated. Finite element method is used for all analyses. Curvature type is assumed to be circular. For the different boundary conditions, natural frequencies of both symmetrical and unsymmetrical tapered beams are given together with that of uniform tapered beam. Bending, torsional, and rotary inertia effects are considered with respect to no-shear effect. Variations of natural frequencies with additional mass and the mass location are examined. Results are given in tabular form. It is concluded that (i) for the uniform tapered beam there is a good agreement between the results of this study and that of literature and (ii) for the symmetrical curved tapered beam there is also a good agreement between the results of this study and that of a finite element model by using MSC.Marc. Results of out-of-plane free vibration of symmetrically tapered beams for specified boundary conditions are addressed.

Stress concentration factors for the torsion of curved beams of arbitrary cross-section

2006 ◽  
Vol 220 (12) ◽  
pp. 1709-1726 ◽  
Author(s):  
R E Cornwell
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Cross Section ◽  
Cross Sections ◽  
Shear Stresses ◽  
Curved Beams ◽  
Finite Element Implementation ◽  
Out Of Plane ◽  
Concentration Factors ◽  
Stress Concentration Factors

There are numerous situations in machine component design in which curved beams with cross-sections of arbitrary geometry are loaded in the plane of curvature, i.e. in flexure. However, there is little guidance in the technical literature concerning how the shear stresses resulting from out-of-plane loading of these same components are effected by the component's curvature. The current literature on out-of-plane loading of curved members relates almost exclusively to the circular and rectangular cross-sections used in springs. This article extends the range of applicability of stress concentration factors for curved beams with circular and rectangular cross-sections and greatly expands the types of cross-sections for which stress concentration factors are available. Wahl's stress concentration factor for circular cross-sections, usually assumed only valid for spring indices above 3.0, is shown to be applicable for spring indices as low as 1.2. The theory applicable to the torsion of curved beams and its finite-element implementation are outlined. Results developed using the finite-element implementation agree with previously available data for circular and rectangular cross-sections while providing stress concentration factors for a wider variety of cross-section geometries and spring indices.

Effects of Out-of-Plane Displacements on Load Capacity of Gusset Plates in Buckling Restrained Braced Frames

2018 ◽  
Vol 763 ◽  
pp. 892-899 ◽  
Author(s):  
Saul Y. Vazquez-Colunga ◽  
Chin Long Lee ◽  
Gregory A. MacRae
Keyword(s):  
Finite Element ◽  
Finite Element Methods ◽  
Load Capacity ◽  
Numerical Results ◽  
Numerical Analyses ◽  
Braced Frames ◽  
Gusset Plates ◽  
Out Of Plane ◽  
Buckling Restrained Braced Frames ◽  
Monotonic Load

This study sets out to investigate the effect of out-of-plane (OOP) displacements on the monotonic load capacity of gusset plates (GPs) via numerical analyses using finite element methods. Two models were used: a) models with in-plane (INP) actions only; and b) models with both INP and OOP actions. The numerical results show that the load capacity of GPs is reduced with the presence of OOP displacements. For an OOP drift of 2.5%, the reduced capacity ranges from 95% to 80% with an average of 88% of the load capacity when only INP actions were applied.

The Effect of Initial Forces on the Hydroelastic Vibration and Stability of Planar Curved Tubes

1974 ◽  
Vol 41 (2) ◽  
pp. 355-359 ◽  
Author(s):  
J. L. Hill ◽  
C. G. Davis
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Constant Curvature ◽  
Elastic Limit ◽  
Center Line ◽  
Finite Element Technique ◽  
Line Shapes ◽  
Circular Arcs ◽  
Out Of Plane ◽  
Element Technique

The effect of initial forces on the vibration and stability of curved, clamped, fluid conveying tubes is analyzed by the finite-element technique. The tubes are initially planar with general center-line shapes approximated by constant curvature arcs. The effect of internal pressure is included. Numerical results are presented with, and without, the effects of the initial in-plane forces, for circular arcs S, L, and spiral configurations. Neglecting initial forces results in out-of-plane buckling, while including these forces prevents buckling within the elastic limit, in all configurations studied.

Fracture assessment of polycarbonate parts produced by fused deposition modeling in the out-of-plane printing direction – effect of raster angle

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Iman Sedighi ◽  
Majid R. Ayatollahi ◽  
Bahador Bahrami ◽  
Marco A. Pérez-Martínez ◽  
Andrés A. Garcia-Granada
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Fracture Behavior ◽  
Fused Deposition Modeling ◽  
Mode I ◽  
Content Type ◽  
Fused Deposition ◽  
Out Of Plane ◽  
Deposition Modeling ◽  
Fracture Tests

Purpose The purpose of this paper is to study the Mode I fracture behavior of polycarbonate (PC) parts produced using fused deposition modeling (FDM). The focus of this study is on samples printed along the out-of-plane direction with different raster angles. Design/methodology/approach Tensile and Mode I fracture tests were conducted. Semi-circular bend specimens were used for the fracture tests, which were printed in four different raster patterns of (0/90), (15/−75) (30/−60) and (45/−45). Moreover, the finite element method (FEM) was used to determine the applicability of linear elastic fracture mechanics (LEFM) for the printed PC parts. The fracture toughness results, as well as the fracture path and the fracture surfaces, were studied to describe the fracture behavior of the samples. Findings Finite element results confirm that the use of LEFM is allowed for the tested PC samples. The fracture toughness results show that changing the direction of the printed rasters can have an effect of up to 50% on the fracture toughness of the printed parts, with the (+45/−45) and (0/90) orientations having the highest and lowest resistance to crack propagation, respectively. Moreover, except for the (0/90) orientation, the other samples have higher crack resistance compared to the bulk material. The fracture toughness of the tested PC depends more on the toughness of the printed sample, rather than its tensile strength. Originality/value The toughness and the energy absorption capability of the printed samples (with different raster patterns) were identified as the main properties affecting the fracture toughness of the AM PC parts. Because the fracture resistance of almost all the samples was higher than that of the base material, it is evident that by choosing the right raster patterns for 3D-printed parts, very high resistance to crack growth may be obtained. Also, using FEM and comparing the size of the plastic zones, it was concluded that, although the tensile curves show nonlinearity, LEFM is still applicable for the printed parts.

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