scholarly journals Numerical High-Order Model for the Nonlinear Elastic Computation of Helical Structures

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Fatima Boussaoui ◽  
Hassane Lahmam ◽  
Bouazza Braikat
Keyword(s):  
Degrees Of Freedom ◽  
Nonlinear Term ◽  
High Order ◽  
Order Model ◽  
Helical Structures ◽  
Asymptotic Numerical Method ◽  
Geometric Type ◽  
Newton Raphson ◽  
Nonlinear Elastic ◽  
Order Algorithm

In this work, we propose a high-order algorithm based on the asymptotic numerical method (ANM) for the nonlinear elastic computation of helical structures without neglecting any nonlinear term. The nonlinearity considered in the following study will be a geometric type, and the kinematics adopted in this numerical modeling takes into account the hypotheses of Timoshenko and de Saint-Venant. The finite element used in the discretization of the middle line of this structure is curvilinear with twelve degrees of freedom. Using a simple example, we show the efficiency of the algorithm which was carried out in this context and which resides in the reduction of the number of inversions of the tangent matrix compared to the incremental iterative algorithm of Newton-Raphson.

ASYMPTOTIC NUMERICAL METHOD FOR THE DYNAMIC STUDY OF NONLINEAR VIBRATION ABSORBERS

2014 ◽  
Vol 06 (05) ◽  
pp. 1450053 ◽  
Author(s):  
FATHI DJEMAL ◽  
FAKHER CHAARI ◽  
JEAN LUC DION ◽  
FRANCK RENAUD ◽  
IMAD TAWFIQ ◽  
...  
Keyword(s):  
Nonlinear Equation ◽  
Vibration Control ◽  
Numerical Method ◽  
Nonlinear Vibration ◽  
Degrees Of Freedom ◽  
Equation Of Motion ◽  
Vibration Absorbers ◽  
Asymptotic Numerical Method ◽  
Dynamic Absorber ◽  
Newton Raphson

Vibrations are usually undesired phenomena as they may cause discomfort, disturbance, damage, and sometimes destruction of machines and structures. It must be reduced or controlled or eliminated. One of the most common methods of vibration control is the use of the dynamic absorber. The paper is interested in the study of a nonlinear two degrees of freedom (DOF) model. To solve nonlinear equation of motion a high order implicit algorithm is proposed. It is based on the introduction of a homotopy, an implicit scheme of Newmark and the use of techniques of Asymptotic Numerical method (ANM). We propose also a regularization of the contact force to overcome the difficulty of the singularity in this model. A comparison will be presented between the results obtained by the proposed algorithm and those using the classical Newton–Raphson and Newmark time scheme.

Method of fundamental solutions and high order algorithm to solve nonlinear elastic problems

2018 ◽  
Vol 89 ◽  
pp. 25-35 ◽  
Author(s):  
Omar Askour ◽  
Abdeljalil Tri ◽  
Bouazza Braikat ◽  
Hamid Zahrouni ◽  
Michel Potier-Ferry
Keyword(s):  
Fundamental Solutions ◽  
High Order ◽  
Method Of Fundamental Solutions ◽  
Nonlinear Elastic ◽  
Order Algorithm

scholarly journals Event-triggered Discrete-time Sliding Mode Control for High-order Systems via Reduced-order Model Approach

2020 ◽  
Vol 53 (2) ◽  
pp. 6207-6212
Author(s):  
Kiran Kumari ◽  
Bijnan Bandyopadhyay ◽  
Johann Reger ◽  
Abhisek K. Behera
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Sliding Mode ◽  
High Order ◽  
Reduced Order Model ◽  
Order Model ◽  
Reduced Order ◽  
Mode Control ◽  
Event Triggered ◽  
Model Approach

scholarly journals Strain-dependent twist–stretch elasticity in chiral filaments

2007 ◽  
Vol 5 (20) ◽  
pp. 303-310 ◽  
Author(s):  
M Upmanyu ◽  
H.L Wang ◽  
H.Y Liang ◽  
R Mahajan
Keyword(s):  
Degrees Of Freedom ◽  
Single Walled Carbon Nanotubes ◽  
Design Principles ◽  
Elastic Behaviour ◽  
Large Strains ◽  
Theoretical Frameworks ◽  
Nonlinear Elastic ◽  
Walled Carbon Nanotubes ◽  
Strain Dependent ◽  
Microscopic Origin

Coupling between axial and torsional degrees of freedom often modifies the conformation and expression of natural and synthetic filamentous aggregates. Recent studies on chiral single-walled carbon nanotubes and B-DNA reveal a reversal in the sign of the twist–stretch coupling at large strains. The similarity in the response in these two distinct supramolecular assemblies and at high strains suggests a fundamental, chirality-dependent nonlinear elastic behaviour. Here we seek the link between the microscopic origin of the nonlinearities and the effective twist–stretch coupling using energy-based theoretical frameworks and model simulations. Our analysis reveals a sensitive interplay between the deformation energetics and the sign of the coupling, highlighting robust design principles that determine both the sign and extent of these couplings. These design principles have already been exploited by nature to dynamically engineer such couplings, and have broad implications in mechanically coupled actuation, propulsion and transport in biology and technology.

scholarly journals New collocation path-following approach for the optimal shape parameter using Kernel method

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Zouhair Saffah ◽  
Abdelaziz Timesli ◽  
Hassane Lahmam ◽  
Abderrahim Azouani ◽  
Mohamed Amdi
Keyword(s):  
Shape Parameter ◽  
Kernel Method ◽  
Continuation Method ◽  
Path Following ◽  
High Order ◽  
Homotopy Continuation ◽  
Homotopy Continuation Method ◽  
Optimal Value ◽  
Rbf Kernel ◽  
Order Algorithm

AbstractThe goal of this work is to develop a numerical method combining Radial Basic Functions (RBF) kernel and a high order algorithm based on Taylor series and homotopy continuation method. The local RBF approximation applied in strong form allows us to overcome the difficulties of numerical integration and to treat problems of large deformations. Furthermore, the high order algorithm enables to transform the nonlinear problem to a set of linear problems. Determining the optimal value of the shape parameter in RBF kernel is still an outstanding research topic. This optimal value depends on density and distribution of points and the considered problem for e.g. boundary value problems, integral equations, delay-differential equations etc. These have been extensively attempts in literature which end up choosing this optimal value by tests and error or some other ad-hoc means. Our contribution in this paper is to suggest a new strategy using radial basis functions kernel with an automatic reasonable choice of the shape parameter in the nonlinear case which depends on the accuracy and stability of the results. The computational experiments tested on some examples in structural analysis are performed and the comparison with respect to the state of art algorithms from the literature is given.

A Hybrid Highly Parallelizable Algorithm for the Dynamics of Rigid Body Chain Systems

1999 ◽  
Author(s):  
Shanzhong Duan ◽  
Kurt S. Anderson
Keyword(s):  
Rigid Body ◽  
Degrees Of Freedom ◽  
High Efficiency ◽  
Equations Of Motion ◽  
Constraint Forces ◽  
Dynamics Of Rigid Body ◽  
A Chain ◽  
Explicit Determination ◽  
Order Algorithm

Abstract The paper presents a new hybrid parallelizable low order algorithm for modeling the dynamic behavior of multi-rigid-body chain systems. The method is based on cutting certain system interbody joints so that largely independent multibody subchain systems are formed. These subchains interact with one another through associated unknown constraint forces f¯c at the cut joints. The increased parallelism is obtainable through cutting the joints and the explicit determination of associated constraint loads combined with a sequential O(n) procedure. In other words, sequential O(n) procedures are performed to form and solve equations of motion within subchains and parallel strategies are used to form and solve constraint equations between subchains in parallel. The algorithm can easily accommodate the available number of processors while maintaining high efficiency. An O[(n+m)Np+m(1+γ)Np+mγlog2Np](0<γ<1) performance will be achieved with Np processors for a chain system with n degrees of freedom and m constraints due to cutting of interbody joints.

scholarly journals Compressible Flow Simulation with Moving Geometries using the Brinkman Penalization in High-Order Discontinuous Galerkin

2020 ◽  
Author(s):  
Neda Ebrahimi Pour ◽  
Nikhil Anand ◽  
Harald Klimach ◽  
Sabine Roller
Keyword(s):  
Degrees Of Freedom ◽  
Flow Simulation ◽  
High Order ◽  
Three Dimensions ◽  
Limiting Factor ◽  
Moving Wall ◽  
Low Dissipation ◽  
Computational Mesh ◽  
Penalization Technique ◽  
Discontinous Galerkin

Abstract In this work we investigate the Brinkman volume penalization technique in the context of a high-order Discontinous Galerkin method to model moving wall boundaries for compressible fluid flow simulations. High-order approximations are especially of interest as they require few degrees of freedom to represent smooth solutions accurately. This reduced memory consumption is attractive on modern computing systems where the memory bandwidth is a limiting factor. Due to their low dissipation and dispersion they are also of particular interest for aeroacoustic problems. However, a major problem for the high-order discretization is the appropriate representation of wall geometries. In this work we look at the Brinkman penalization technique, which addresses this problem and allows the representation of geometries without modifying the computational mesh. The geometry is modelled as an artificial porous medium and embedded in the equations. As the mesh is independent of the geometry with this method, it is not only well suited for highorder discretizations but also for problems where the obstacles are moving.We look into the deployment of this strategy by briefly discussing the Brinkman penalization technique and its application in our solver and investigate its behavior in fundamental one-dimensional setups, such as shock reflection at a moving wall and the formation of a shock in front of a piston. This is followed by the application to setups with two and three dimensions, illustrating the method in the presence of curved surfaces.

Quasi-Static Modelling and Computer Simulation of Hanging Cables on Robots

1994 ◽  
Author(s):  
Li-Ping Yang ◽  
Shin-Min Song
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Finite Segment ◽  
Revolute Joints ◽  
Highly Nonlinear ◽  
Finite Segment Method ◽  
Newton Raphson ◽  
Static Modelling ◽  
Parameter Perturbation Method ◽  
Raphson Method

Abstract This paper presents a computer method to simulate the quasi-static motion of hanging cables on robots. The shape of the flexible cable is changing during motion and the finite segment method is applied to determine its configuration. The cable is modeled as a series of rigid segments segments connected together through revolute joints in 2-D case and spherical joints in 3-D case. The elasticity of cable is represented by torsional springs at the joints. In both cases, a set of highly nonlinear equations are derived based on force equilibrium and the Newton-Raphson method is applied to calculate the solution. In order to assure convergence and improve computational efficiency, the parameter perturbation method is applied together with the Newton-Raphson method. Also, some computational strategies are developed to simplify the three dimensional problem. Finally, the developed methods are demonstrated in displaying the motion of a hanging cable which is attached to a revolute joint, a prismatic joint and a three degrees of freedom robot.

Sign in / Sign up

Export Citation Format

Share Document