Advances In The Modeling And Dynamic Simulation of Reeving Systems Using The Arbitrary Lagrangian-Eulerian Modal Method

2021 ◽  
Author(s):  
José L. Escalona ◽  
Narges Mohammadi
Keyword(s):  
Finite Elements ◽  
Axial Force ◽  
Axial Direction ◽  
Rotary Inertia ◽  
Arbitrary Lagrangian Eulerian ◽  
Original Formulation ◽  
Absolute Position ◽  
Axial Forces ◽  
Modal Coordinates ◽  
Modal Method

Abstract This paper presents new advances in the arbitrary Lagrangian-Eulerian modal method (ALEM) recently developed for the systematic simulation of the dynamics of general reeving systems. These advances are related to a more convenient model of the sheaves dynamics and the use of axial deformation modes to account for non-constant axial forces within the finite elements. Regarding the sheaves dynamics, the original formulation uses kinematic constraints to account for the torque transmission at the sheaves by neglecting the rotary inertia. One of the advances described in this paper is the use of the rotation angles of the sheaves as generalized coordinates together with the rope-to-sheave no-slip assumption as linear constraint equations. This modeling option guarantees the exact torque balance the sheave without including any non-linear kinematic constraint. Numerical results show the influence in the system dynamics of the sheave rotary inertia. Regarding the axial forces within the finite elements, the original formulation uses a combination of absolute position coordinates and transverse local modal coordinates to account for the rope absolute position and deformation shape. The axial force, which only depends on the absolute position coordinates, is constant along the element because linear shape functions are assumed to describe the axial displacements. For reeving systems with very long rope spans, as the elevators of high buildings, the constant axial force is inaccurate because the weight of the ropes becomes important and the axial force varies approximately linearly within the rope free span. To account for space-varying axial forces, this paper also introduces modal coordinates in the axial direction. Numerical results show that a set of three modal coordinates in the axial direction is enough to simulate linearly varying axial forces.

Dynamic Simulation of Reeving Systems With the Extension of the Modal Approach in the Axial Direction

2021 ◽  
Author(s):  
Narges Mohammadi ◽  
José Luis Escalona
Keyword(s):  
Axial Strain ◽  
Equations Of Motion ◽  
Axial Direction ◽  
Rigid Bodies ◽  
Arbitrary Lagrangian Eulerian ◽  
Absolute Nodal Coordinates ◽  
Lagrange’S Equation ◽  
Axial Forces ◽  
Nodal Coordinates ◽  
Modal Coordinates

Abstract In this work, the simulation of reeving systems has been studied by including axial modes using the Arbitrary Lagrangian-Eulerian (ALE) description. The reeving system is considered as a deformable multibody system in which the rigid bodies are connected by the elastic wire ropes through sheaves and reels. A set of absolute nodal coordinates and modal coordinates is employed to describe the motion and deformation in the axial direction. This new method allows the analysis of elements with non-constant axial strain along its length. In addition, modal coordinates are employed to describe the dynamic motion in the transverse direction. The non-constant axial displacement within the wire rope is computed in terms of the absolute position coordinates, longitudinal material coordinates, and modal deformation coordinates. To derive the governing equations of motion, Lagrange’s equation is employed. The formulation is validated for a simple pendulumlike motion actuated by an initial velocity. The simulation results are provided to trace the movements of the payload. It can be seen that by adding modal coordinates, the axial force within the element changes. Moreover, the effects of modal coordinates in the axial direction are presented for a different number of nodes, and the resulting axial forces are compared with reference solution.

scholarly journals Driven Pile Effects on Nearby Cylindrical and Semi-Tapered Pile in Sandy Clay

2021 ◽  
Vol 11 (7) ◽  
pp. 2919
Author(s):  
Massamba Fall ◽  
Zhengguo Gao ◽  
Becaye Cissokho Ndiaye
Keyword(s):  
Coupling Effect ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Adaptive Mesh ◽  
Pile Driving ◽  
Arbitrary Lagrangian Eulerian ◽  
Axial Forces ◽  
Tapered Pile ◽  
Driven Pile ◽  
The Impact

A pile foundation is commonly adopted for transferring superstructure loads into the ground in weaker soil. They diminish the settlement of the infrastructure and augment the soil-bearing capacity. This paper emphases the pile-driving effect on an existing adjacent cylindrical and semi-tapered pile. Driving a three-dimensional pile into the ground is fruitfully accomplished by combining the arbitrary Lagrangian–Eulerian (ALE) adaptive mesh and element deletion methods without adopting any assumptions that would simplify the simulation. Axial forces, bending moment, and lateral displacement were studied in the neighboring already-installed pile. An investigation was made into some factors affecting the forces and bending moment, such as pile spacing and the shape of the already-installed pile (cylindrical, tapered, or semi-tapered). An important response was observed in the impact of the driven pile on the nearby existing one, the bending moment and axial forces were not negligible, and when the pile was loaded, it was recommended to consider the coupling effect. Moreover, the adjacent semi-tapered pile was subjected to less axial and lateral movement than the cylindrical one with the same length and volume for taper angles smaller than 1.0°, and vice versa for taper angles greater than 1.4°.

Co-Simulation Procedure for Multibody Reeving Systems

2018 ◽  
Author(s):  
Grzegorz Orzechowski ◽  
Aki M. Mikkola ◽  
José L. Escalona
Keyword(s):  
Multibody System ◽  
Wire Rope ◽  
Rigid Bodies ◽  
Arbitrary Lagrangian Eulerian ◽  
Transverse Deformation ◽  
Absolute Position ◽  
Eulerian Approach ◽  
Wire Ropes ◽  
Simulation Procedure ◽  
Flexible Wire

In this paper, co-simulation procedure for a multibody system that includes reeving mechanism will be introduced. The multibody system under investigation is assumed to have a set of rigid bodies connected by flexible wire ropes using a set of sheaves and reels. In the co-simulation procedure, a wire rope is described using a combination of absolute position coordinates, relative transverse deformation coordinates and longitudinal material coordinates. Accordingly, each wire rope span is modeled using a single two-noded element by employing an Arbitrary Lagrangian-Eulerian approach.

scholarly journals Axial Force at the Vessel Bottom Induced by Axial Impellers

10.14311/1039 ◽  
2008 ◽  
Vol 48 (4) ◽  
Author(s):  
I. Fořt ◽  
P. Hasal ◽  
A. Paglianti ◽  
F. Magelli
Keyword(s):  
Axial Force ◽  
Axial Direction ◽  
Liquid Jet ◽  
Turbulent Regime ◽  
Flat Bottom ◽  
Stirred Vessel ◽  
Pressure Transducers ◽  
The Mean ◽  
Mean Time ◽  
Vessel Bottom

This paper deals with the axial force affecting the flat bottom of a cylindrical stirred vessel. The vessel is equipped with four radial baffles and is stirred with a four 45° pitched blade impeller pumping downwards. The set of pressure transducers is located along the whole radius of the flat bottom between two radial baffles. The radial distribution of the dynamic pressures indicated by the transducers is measured in dependence on the impeller off-bottom clearance and impeller speed.It follows from the results of the experiments that under a turbulent regime of flow of an agitated liquid the mean time values of the dynamic pressures affecting the bottom depend not on the impeller speed but on the impeller off-bottom clearance. According to the model of the flow pattern of an agitated liquid along the flat bottom of a mixing vessel with a pitched blade impeller, three subregions can be considered in this region: the liquid jet streaming downwards from the impeller deviates from its vertical (axial) direction to the horizontal direction,  the subregion of the liquid flowing horizontally along the bottom and, finally, the subregion of the liquid changing direction from the bottom upwards (vertically) along the wall of the cylindrical vessel, when the volumetric flow rates of the liquid taking place in the downward and upward flows are the same. 

Measurement of axial forces during emptying from the human stomach

1992 ◽  
Vol 263 (2) ◽  
pp. G230-G239 ◽  
Author(s):  
M. J. Vassallo ◽  
M. Camilleri ◽  
C. M. Prather ◽  
R. B. Hanson ◽  
G. M. Thomforde
Keyword(s):  
Axial Force ◽  
Longitudinal Axis ◽  
Force Transducer ◽  
Human Stomach ◽  
In Vitro Studies ◽  
In Vivo Studies ◽  
Dependent Manner ◽  
Axial Forces

Our aim was to measure axial forces in the stomach and to evaluate their relation to circumferential contractions of the gastric walls and the emptying of gastric content. We used a combination of simultaneous radioscintigraphy, gastroduodenal manometry, and an axial force transducer with an inflatable 2-ml balloon fluoroscopically placed in the antrum. In vitro studies demonstrated that the axial force transducer records only antegrade forces along the longitudinal axis of this probe in an intensity-dependent manner. In vivo studies were performed in five healthy subjects for at least 3 h after ingestion of radiolabeled meals. When administered separately, the emptying of liquids or solids from the stomach is associated with generation of antral axial forces and coincident phasic pressure activity; however, almost 20% (average) of gastric axial forces during emptying of liquids or solids are unassociated with proximal or distal antral pressure activity ("isolated" forces). High amplitude antral axial forces and pressures occur during both lag and postlag emptying phases. During emptying of liquids, there is a trend for axial forces to be coincident more often with proximal than with distal antral pressure activity and vice versa for the emptying of solids (P = 0.015). These data suggest that when placed in the antrum, the transducer can semiquantitatively record axial forces during gastric emptying. By combining these observations with the data from in vitro studies, it appears that axial forces predominantly result from traction on the balloon by the longitudinal vector resulting from circumferential gastric contractions. The combination of radioscintigraphy and measurement of antral axial forces is a promising method to evaluate mechanical forces involved in the emptying of the human stomach.

Analytical Computational Models for Relationship between Ultimate Bending Moment of Concrete Segments and Axial Force

2020 ◽  
Vol 853 ◽  
pp. 177-181
Author(s):  
Zhi Yun Wang ◽  
Shou Ju Li
Keyword(s):  
Numerical Simulation ◽  
Computational Model ◽  
Axial Force ◽  
Computational Models ◽  
Plane Deformation ◽  
Bending Moment ◽  
Analytical Models ◽  
Bending Moments ◽  
Axial Forces ◽  
Practical Engineering

Concrete segments are widely used to support soil and water loadings in shield-excavated tunnels. Concrete segments burden simultaneously to the loadings of bending moments and axial forces. Based on plane deformation assumption of material mechanics, in which plane section before bending remains plane after bending, ultimate bending moment model is proposed to compute ultimate bearing capacity of concrete segments. Ultimate bending moments of concrete segments computed by analytical models agree well with numerical simulation results by FEM. The accuracy of proposed analytical computational model for ultimate bending moment of concrete segments is numerically verified. The analytical computational model and numerical simulation for a practical engineering case indicate that the ultimate bending moment of concrete segments increases with increase of axial force on concrete segment in the case of large eccentricity compressive state.

Evaluation of foundation tie requirements in seismic design

1993 ◽  
Vol 20 (1) ◽  
pp. 73-81
Author(s):  
A. C. Heidebrecht ◽  
A. Rutenberg
Keyword(s):  
Axial Force ◽  
Seismic Design ◽  
Structural Model ◽  
Travelling Waves ◽  
Travelling Wave ◽  
Shear Forces ◽  
Seismic Codes ◽  
Axial Forces ◽  
Pile Caps ◽  
Spread Footings

A simple structural model is proposed to evaluate the axial force acting on tie beams interconnecting spread footings or pile caps due to differential ground motion estimated on the basis of the travelling wave assumption. The approach is intended to supplement the "ten percent rule" or similar multipliers specified by seismic codes as design axial forces on tie beams. It is shown that the axial force demand is rather modest. However, shear forces between footing and soil may be quite large depending on maximum column displacements and superstructure rigidity. Key words: foundations, tie beams, earthquake, travelling waves, seismic codes.

Numerical Simulation of Friction Stir Welding (FSW) Process Based on ABAQUS Environment

2016 ◽  
Vol 254 ◽  
pp. 272-277
Author(s):  
Monica Iordache ◽  
Claudiu Bădulescu ◽  
Eduard Niţu ◽  
Doina Iacomi
Keyword(s):  
Numerical Simulation ◽  
Friction Stir Welding ◽  
Finite Elements ◽  
Adaptive Mesh ◽  
Experimental Tests ◽  
Arbitrary Lagrangian Eulerian ◽  
Complex Issue ◽  
Friction Stir ◽  
Mechanical Phenomena

. Simulation of the FSW process is a complex issue, as it implies interactions between thermal and mechanical phenomena and the quality of the welding depends on many factors. In order to reduce the time of the experimental tests, which can be long and expensive, numerical simulation of the FSW process has been tried during the last ten years. However, there still remain aspects that cannot be completely simulated. In this paper the authors present the steps of the numerical simulation using the finite elements method, in order to evaluate the boundary conditions of the model and the geometry of the tools by using the Arbitrary Lagrangian Eulerian (ALE) adaptive mesh controls.

Study on Isolated Layer Mechanics Character of Combined Base Isolated Structure Based on Axial Forces Redistribute

2012 ◽  
Vol 166-169 ◽  
pp. 627-631 ◽  
Author(s):  
Fu You Zhang ◽  
Ming Gu ◽  
Yun Song ◽  
Song Xu
Keyword(s):  
Axial Force ◽  
Horizontal Displacement ◽  
Vertical Force ◽  
Isolation System ◽  
Isolation Layer ◽  
Calculating Method ◽  
Axial Forces ◽  
Rubber Bearings

Abstract：Combined isolation system is combined with rubber bearings which provide resilience forces and sliding isolated bearings which provide damp. According to the rule of axial forces redistributing between two kinds of bearings under earthquake, a calculating method considering the vertical force redistribute of isolation layer was given. With this method, the results of an example show that axial force will transfer from rubber bearings to sliding isolated bearings along with the horizontal displacement of isolation layer. The bigger the displacement is the more axial force transfers. So the axial-forces redistribution is a self-adjustable performance of the system, and also is an advantage for the system.

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