scholarly journals Optimization of a Truss Structure Used to Design of the Manipulator Arm from a Set of Components

2021 ◽  
Vol 11 (21) ◽  
pp. 10193
Author(s):  
Jaroslav Rojíček ◽  
Zbyněk Paška ◽  
Martin Fusek ◽  
Zdenko Bobovsky ◽  
Alžbeta Sapietová ◽  
...  
Keyword(s):  
Shell Element ◽  
Truss Structure ◽  
Topological Optimization ◽  
Truss Structures ◽  
The Finite Element Method ◽  
Simple Task ◽  
Shell Elements ◽  
Python Language ◽  
Manipulator Arm ◽  
Construction Kit

The design of a manipulator arm, which is built from a construction kit, is presented in this article. The procedure is based on the results of the discrete optimization of a truss structure and its application to a simple component system (assuming a predefined shape and material of components). A genetic algorithm is used to optimize the truss structure, and the results of the solution are verified on a simple task used in literature (the code was written in the Python language). The construction kit was inspired by Merkur®, and the article proposes several components with different shapes and materials. The construction kit and the optimization of the truss structure were used to design the manipulator arm. The truss topology has been predefined with respect to the construction set. The finite element method (software ANSYS®) was used to analyze the components (shell elements) and truss structures (linear analysis, buckling analysis, etc.). To validate the presented approach, the arm designed by topological optimization was used. The comparison shows that the use of components may be an alternative to topology optimization and additive manufacturing. The next step will be the modification of the presented method in order to minimize the differences between the simplified task used for optimization (truss structure-rod element) and the simulation composed of components (components assembly-shell element).

A Two Step Damage Prognosis Method for Beam-Like Truss Structures

2014 ◽  
Vol 578-579 ◽  
pp. 1092-1095
Author(s):  
Hao Kai Jia ◽  
Ling Yu
Keyword(s):  
Finite Element Method ◽  
Strain Energy ◽  
Truss Structure ◽  
Truss Structures ◽  
Second Step ◽  
The Finite Element Method ◽  
Modal Strain Energy ◽  
Damage Prognosis ◽  
Modal Curvature ◽  
Simulation Results

In this study, a two step damage prognosis method is proposed for beam-like truss structures via combining modal curvature change (MCC) with modal strain energy change ratio (MSECR). Changes in the modal curvature and the elemental strain energy are selected as the indicator of damage prognosis. Different damage elements with different damage degrees are simulated. In the first step, the finite element method is used to model a beam-like truss structure and the displacement modes are got. The damage region is estimated by the MCC of top and bottom chords of a beam-like truss structure. In the second step, the elemental MSECR in the damage region is calculated and the maximum MSECR element is deemed as the damage element. The simulation results show that this method can accurately locate the damage in the beam-like truss structure.

Application of Topological Optimization Techniques to Automotive Front Structure Design

2001 ◽  
Author(s):  
Robert R. Mayer
Keyword(s):  
Optimization Technique ◽  
Shell Element ◽  
Optimality Criteria ◽  
Structure Design ◽  
Optimization Techniques ◽  
Design Concept ◽  
Topological Optimization ◽  
Shell Elements ◽  
Front Structure ◽  
Design Variables

Abstract An application of topological optimization techniques to automotive front structure design was considered, for the case of crashworthiness performance. An earlier developed topological optimization technique was used by first deriving an optimality criteria. To develop an optimality criteria, a functional relationship was developed between microstructure design variables, and both strain energy and volume, for shell element structures. Its previous application was the location of holes to lighten a rear longitudinal rail. The present application applies this theory to the actual layout of automotive front structure. The nonlinear code, LS-DYNA, was used for the simulations. An observation of various automotive front structural topologies, sometimes called structural layouts or architectures, reveals that many different design approaches are possible. In order to numerically assess the optimum layout the design space available for front structure design is built up from layers of shell elements, and the method of constructing these models using LS-INGRID is discussed. Some of these elements are deleted at each optimization iteration, resulting in a design concept. The design concept is interpreted as a number of structural load paths, and a unique design was then identified.

A Finite Element for the Analysis of Shell Intersections

1996 ◽  
Vol 118 (4) ◽  
pp. 399-406 ◽  
Author(s):  
W. J. Koves ◽  
S. Nair
Keyword(s):  
Finite Element ◽  
Stress State ◽  
Three Dimensional ◽  
Shell Element ◽  
Theory Of Elasticity ◽  
Shell Elements ◽  
Asme Code ◽  
Form Theory ◽  
Computation Scheme ◽  
Shell Intersections

A specialized shell-intersection finite element, which is compatible with adjoining shell elements, has been developed and has the capability of physically representing the complex three-dimensional geometry and stress state at shell intersections (Koves, 1993). The element geometry is a contoured shape that matches a wide variety of practical nozzle configurations used in ASME Code pressure vessel construction, and allows computational rigor. A closed-form theory of elasticity solution was used to compute the stress state and strain energy in the element. The concept of an energy-equivalent nodal displacement and force vector set was then developed to allow complete compatibility with adjoining shell elements and retain the analytical rigor within the element. This methodology provides a powerful and robust computation scheme that maintains the computational efficiency of shell element solutions. The shell-intersection element was then applied to the cylinder-sphere and cylinder-cylinder intersection problems.

scholarly journals Modelling of confined masonry structure and its application for the design of multi-story building

2019 ◽  
Vol 276 ◽  
pp. 01034
Author(s):  
Made Sukrawa ◽  
Gede Pringgana ◽  
Putu Ayu Ratih Yustinaputri
Keyword(s):  
Maximum Stress ◽  
Residential Building ◽  
Shell Element ◽  
Reinforced Concrete Beams ◽  
Seismic Load ◽  
Confined Masonry ◽  
Shell Elements ◽  
Wall Strength ◽  
Story Building ◽  
Better Than

The confined masonry (CM) structure has been commonly used in the construction of one-story buildings in Indonesia. Its application for multi-story buildings however, is not yet as popular as the alternative options. This research numerically investigated the behavior of confined masonry and its application for use as the main structure of multi-story buildings subjected to seismic loading. From the validation models it was revealed that, using shell element for masonry walls, reinforced concrete beams and tie-columns, the CM model mimic the load deformation curve of tested specimen better than that using frame and shell elements. The application of the modeling technique for the design of 3-story residential building using wall density index less than that suggested in the literature resulted in a safe and stiff structure. The wall stresses under design seismic load were still less than the wall strength and the drift ratio of the model was 0.06% much smaller than the limit of 0.2%. The maximum stress observed at the corners of wall opening justify the need for confinement along the opening.

scholarly journals Numerical Simulation and Experimental Testing of Topologically Optimized PLA Cervical Implants Made by Additive Manufacturing Methodics

2018 ◽  
Vol 12 (2) ◽  
pp. 141-144
Author(s):  
Jozef Živčák ◽  
Radovan Hudák ◽  
Marek Schnitzer ◽  
Tomáš Kula
Keyword(s):  
Additive Manufacturing ◽  
Static Loading ◽  
Surgical Intervention ◽  
Experimental Testing ◽  
Axial Loading ◽  
Topological Optimization ◽  
Optimized Design ◽  
The Finite Element Method ◽  
3D Printed ◽  
Cervical Area

Abstract The article focuses on compressive axial loading experimental testing and simulations of topologically optimized design and additively manufactured cervical implants. The proposed platform design is based on anatomical and biomechanical requirements for application in the cervical area. Thanks to new ways of production, such as additive manufacturing, and new software possibilities in the field of structural analysis, which use the finite element method and analysis, it is possible to execute topological optimization of an implant in construction solution, which would be impossible to make by conventional methods. The contribution of this work lies in investigation of 3D printed PLA cervical implant usage in surgical intervention and creation of a numerical static loading modelling methodics and subsequent experimental confirmation of the modelling correctness.

scholarly journals RESPON SEISMIK STRUKTUR RANGKA DINDING PENGISI YANG DIMODEL DENGAN ELEMEN SHELL PENUH DAN PARSIAL

2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Putu Ratna Suryantini ◽  
M. Sukrawa ◽  
I. A. M Budiwati
Keyword(s):  
Shell Model ◽  
3D Structure ◽  
Shell Element ◽  
Maximum Load ◽  
3D Models ◽  
Frame Structure ◽  
Natural Period ◽  
Shell Elements ◽  
Frame Model ◽  
Wall Strength

Abstract: Research on the seismic response of in-filled frame structure has been done with in-filled frame model as full and partial shell elements. The wall is considered active until the maximum load on the full shell models, while the partial shell model using the gradual load with the strength of the wall is considered inactive if the stress of the wall exceeded the wall strength The 4 storey hotel building with full wall in x-direction and wall with opening in y-direction were modeled in SAP 2000 as 3D infilled-frame using full and partial shell element. In Mxy models, both wall were included in the model, while in My models, only the wall in y-direction included. Therefore, 4 models were obtained, there are full shell model MxyShPn and MyShPn and partial shell model MyShPar and MyShPar. In addition, 2 diagonal strut models MxyS and MyS  and an open frame model MOF were made as comparison. Prior to model 3D structure, validation models were created using test result condited by other as reference. For that purphose 5 2D models were created there are open frame model MOF, single strut model MST, multiple strut model MSG, full shell model MShPn and  partial shell model MShPar. From validation models, it is apparent that the MxyShPar model mimic the behavior of tested structure better than the other models. From the 3D models analysis result show that the displacement in x-direction of MxyShPn, MxyShPar, MxyS were 89%, 85%, 84% smaller than those of MOF, respectively inclusion of wall in the models, also reduce the internal forces and reduse the natural period of the sctructure.

Simulating welding with shell elements

2004 ◽  
Vol 120 ◽  
pp. 347-354
Author(s):  
F. Faure ◽  
J.-M. Bergheau ◽  
J.-B. Leblond
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Shell Element ◽  
Thermal Calculation ◽  
Transformation Plasticity ◽  
Thin Structures ◽  
Shell Elements ◽  
Mechanical Calculation ◽  
Complex Interactions ◽  
Mechanical Phenomena

Finite element simulations can be used to evaluate residual stresses and distortions induced by welding. Such simulations must account for complex interactions between thermal, metallurgical and mechanical phenomena. “Local” simulations are often sufficient for satisfactory predictions of residual stresses in the heat-affected zone (HAZ), but 3D “global” simulations are often necessary to calculate distortions, which can be important even far from the HAZ. In order to avoid such heavy calculations, a special shell element is proposed for the simulation of welding of thin structures. The thermal calculation involves only one nodal degree of freedom but fully accounts for boundary conditions on the faces of the shell. The metallurgical and mechanical calculations are based on a “multi-layer” approach. Due account is taken of transformation plasticity in the mechanical calculation. Numerical results obtained with this approach are compared to those of experiments and some 3D simulation.

Locking Behavior of Isoparametric Curved Beam Finite Elements

1995 ◽  
Vol 48 (11S) ◽  
pp. S25-S29 ◽  
Author(s):  
Miguel Luiz Bucalem ◽  
Klaus-Ju¨rgen Bathe
Keyword(s):  
Shell Element ◽  
Beam Element ◽  
Curved Beam ◽  
Shear Locking ◽  
Shell Elements ◽  
One Dimensional ◽  
Curved Beam Element ◽  
The One ◽  
Insight Into ◽  
The Continuum

We present a study of the membrane and shear locking behavior in an isoparametric curved beam element. The objective is to gain insight into the locking phenomenon, specially membrane locking, of continuum based degenerated shell elements. This is possible since the isobeam element is the one-dimensional analogue of the continuum based shell element. In this context, reduced integration and mixed interpolation schemes are briefly examined. Such a study can be a valuable aid when developing new shell elements.

A Curved C0 Shell Element Based on Assumed Natural-Coordinate Strains

1986 ◽  
Vol 53 (2) ◽  
pp. 278-290 ◽  
Author(s):  
K. C. Park ◽  
G. M. Stanley
Keyword(s):  
Shell Element ◽  
Benchmark Problems ◽  
Integration Rule ◽  
Shell Elements ◽  
Curvature Effects ◽  
Point Integration ◽  
Membrane Bending ◽  
Transverse Shear Locking ◽  
Natural Coordinate ◽  
Membrane Strain

A curved C0 shell element is presented, which corrects several deficiencies in existing quadratic shell elements. The improvements realized in the present element include rank sufficiency without transverse shear locking, consistent membrane strain interpolation that admits inextensional bending without reduced integration, and adequate representation of curvature effects to capture the important membrane-bending coupling. The element can be constructed either by a nine-point integration rule or by a four-point integration rule with the proper rank compensating terms. Numerical experiments with the present element on several benchmark problems indicate that the element yields accurate and reliable solutions without any ostensible deficiency. The element is recommended for production analysis of shell structures.

Comparison Between Numerical Simulation and Experimentation of Asymmetrical Three-Roll Bending Process

2010 ◽  
Author(s):  
Zhengkun Feng ◽  
Henri Champliaud
Keyword(s):  
Structural Dynamics ◽  
Metal Forming ◽  
Plastic Material ◽  
Time Integration ◽  
Material Model ◽  
Rigid Bodies ◽  
The Finite Element Method ◽  
Shell Elements ◽  
Roll Bending ◽  
Bending Process

Three-roll bending processes are widely used in metal forming manufacturing due to simple configurations. Asymmetrical three-roll bending is one of the processes. This paper deals with the simulation analyses based on the finite element method for cylindrical production. The components of the roll bending machine, such as the rolls were assumed to be rigid bodies and the 4-node shell elements were used in the modeling. The tensile test of the material was simulated to determine the elasto-plastic material model of the plate. Automatic node-surface contacts were chosen for the interfaces between the plate and the rigid bodies. The nonlinear equations which represent the structural dynamics with large displacement were resolved using explicit time integration. The simulations were performed under the well-known ANSYS/LS-DYNA environment. The numerical results agree well with the experimental ones.

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