Identification of Boundary Forces in Beams From Measured Displacements

2006 ◽  
Vol 128 (6) ◽  
pp. 757-771 ◽  
Author(s):  
S. Chesne ◽  
C. Pezerat ◽  
J. L. Guyader
Keyword(s):  
Numerical Simulation ◽  
Shear Force ◽  
Good Accuracy ◽  
Bending Moment ◽  
Weak Form ◽  
Equation Of Motion ◽  
Test Functions ◽  
Direct Measurements ◽  
Simulation Results ◽  
Measured Displacement

This paper deals with shear force and bending moment identification in a beam from measured displacement. The proposed approach, using the weak form of the equation of motion, is based on the extraction of shear force or bending moment from integral equation and choice of test functions, associated to each boundary quantity of interest. After the theorical description, numerical simulation results are shown in order to clarify limits of the method and to stress its self-regularization. Two experimentations are described, showing very good accuracy of shear force and bending moment reconstruction in comparison with direct measurements.

Numerical Simulation by CGM for Moving Force Identification

2012 ◽  
Vol 238 ◽  
pp. 826-829
Author(s):  
Zhen Chen ◽  
Jun Ling Han
Keyword(s):  
Numerical Simulation ◽  
Time Domain ◽  
Bending Moment ◽  
Identification Accuracy ◽  
Time Varying ◽  
Acceptable Solution ◽  
Moving Force ◽  
Ill Posed ◽  
Simulation Results ◽  
The Time Domain

The conjugate gradient method (CGM) is compared with the time domain method (TDM) in the paper. The numerical simulation results show that the CGM have higher identification accuracy and robust noise immunity as well as producing an acceptable solution to ill-posed problems to some extent when they are used to identify the moving force. When the bending moment responses are used to identify the time-varying loads, the identification accuracy is more obviously improved than the TDM, which is more suitable for the time-varying loads identification.

Identification of Plate Boundary Forces From Measured Displacements

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Simon Chesne ◽  
Charles Pezerat ◽  
Jean-Louis Guyader
Keyword(s):  
Measurement Errors ◽  
Shear Force ◽  
Plate Boundary ◽  
Bending Moment ◽  
Direct Calculation ◽  
Weak Form ◽  
Plate Boundaries ◽  
Test Function ◽  
Highly Sensitive ◽  
Definition Of

This work deals with the identification of forces at plate boundaries, by measuring displacements only. Shear force and bending moment directly depend on different spatial derivatives of displacement at plate boundaries that can be approximated from measured displacements (finite differences, modal approach, etc.), but two major difficulties occur: Derivatives are highly sensitive to measurement errors and the usual methods used to obtain them are not well adapted to boundary points. In this paper, a mathematical approach is proposed to identify shear force at boundaries without any direct calculation of the displacement derivatives. The method is based on the weak form of the plate equation of motion and a test function satisfying particular boundary conditions. Following the description of the technique and the definition of the test function that permits the identification at one boundary point, numerical simulation results, including the effects of noise on displacements, are provided in order to establish the spatial and frequency limits of this method.

Study on Engineering Materials with the Comparison and Discussion of Support Scheme in a Foundation Pit

2013 ◽  
Vol 788 ◽  
pp. 623-626
Author(s):  
Zheng Zhen ◽  
Ren Wang Liang
Keyword(s):  
Numerical Simulation ◽  
Shear Force ◽  
Simulation Analysis ◽  
Bending Moment ◽  
Engineering Material ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Cost Performance ◽  
Deep Foundation Pit ◽  
Practical Engineering

Taking a deep foundation pit engineering in Taiyuan as research background, this paper used two different supporting structure of foundation pit to make numerical simulation analysis by using Li zheng software. The engineering material had high cost performance. In addition, the paper studied the displacement, bending moment, shear force with the change of the excavation depth, and it came to the conclusion that some outcome can be used for reference in the practical engineering.

Numerical Simulation and Wind Tunnel Studies of the Wind Load on Wind Turbine Structures

2011 ◽  
Vol 250-253 ◽  
pp. 3811-3814
Author(s):  
Cheng Hsin Chang ◽  
Jen Mu Wang ◽  
Chii Ming Cheng
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Tunnel Test ◽  
Bending Moment ◽  
Dynamic Mesh ◽  
Base Shear ◽  
Structural Responses ◽  
Simulation Results ◽  
Rng Turbulence Model

This paper investigated the structural responses of the wind turbine due to wind loads by performing the wind tunnel test and the Computational Fluid Dynamics, (CFD). The base shear force and the base moment of the wind turbine measured by the wind tunnel test were compared with the numerical simulation results. Both the numerical dynamic mesh and sliding mesh models were selected for the numerical simulations. The results showed that the dynamic mesh model was better than the sliding model by comparing to the wind tunnel test result. In the case of the k-epsilon RNG turbulence model, the prediction of the bending moment affecting by acrossswind was more than 50%, and the prediction of the force affecting by acrosswind was less than 3%. The both simulation results of the prototype and the full scale wind turbine were obtained by CFD model. The comparisons of the result showed that the error of Fxwas about 15% and Mywas about 13.5%.

Avalanche Features in Silicon Schottky-FETs in Accordance with Numerical Simulation Results

2006 ◽  
Vol 65 (16) ◽  
pp. 1533-1546
Author(s):  
Yu. Ye. Gordienko ◽  
S. A. Zuev ◽  
V. V. Starostenko ◽  
V. Yu. Tereshchenko ◽  
A. A. Shadrin
Keyword(s):  
Numerical Simulation ◽  
Simulation Results

Tail shapes lead to different propulsive mechanisms in the body/caudal fin undulation of fish

2020 ◽  
pp. 095440622096768
Author(s):  
Jialei Song ◽  
Yong Zhong ◽  
Ruxu Du ◽  
Ling Yin ◽  
Yang Ding
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Efficiency ◽  
The Body ◽  
Caudal Fin ◽  
Fish Model ◽  
Swimming Efficiency ◽  
Simulation Results ◽  
Propulsive Mechanism ◽  
High Depth

In this paper, we investigate the hydrodynamics of swimmers with three caudal fins: a round one corresponding to snakehead fish ( Channidae), an indented one corresponding to saithe ( Pollachius virens), and a lunate one corresponding to tuna ( Thunnus thynnus). A direct numerical simulation (DNS) approach with a self-propelled fish model was adopted. The simulation results show that the caudal fin transitions from a pushing/suction combined propulsive mechanism to a suction-dominated propulsive mechanism with increasing aspect ratio ( AR). Interestingly, different from a previous finding that suction-based propulsion leads to high efficiency in animal swimming, this study shows that the utilization of suction-based propulsion by a high- AR caudal fin reduces swimming efficiency. Therefore, the suction-based propulsive mechanism does not necessarily lead to high efficiency, while other factors might play a role. Further analysis shows that the large lateral momentum transferred to the flow due to the high depth of the high- AR caudal fin leads to the lowest efficiency despite the most significant suction.

scholarly journals Experiment and simulation about the effect of wear-ring abrasion on the performance of a marine centrifugal pump

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199811
Author(s):  
Wu Xianfang ◽  
Du Xinlai ◽  
Tan Minggao ◽  
Liu Houlin
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Vibration Velocity ◽  
Test Results ◽  
Obvious Effect ◽  
Performance Change ◽  
Pump Test ◽  
Simulation Results ◽  
Axis Passing

The wear-ring abrasion can cause performance degradation of the marine centrifugal pump. In order to study the effect of front and back wear-ring clearance on a pump, test and numerical simulation were used to investigate the performance change of a pump. The test results show that the head and efficiency of pump decrease by 3.56% and 9.62% respectively at 1.0 Qd due to the wear-ring abrasion. Under 1.0 Qd, with the increase of the front wear-ring the vibration velocity at pump foot increases from 0.4 mm/s to 1.0 mm/s. The axis passing frequency (APF) at the measuring points increases significantly and there appears new characteristic frequency of 3APF and 4APF. The numerical simulation results show that the front wear-ring abrasion affects the flow at the inlet of the front chamber of the pump and impeller passage. And the back wear-ring abrasion has obvious effect on the flow in the back chamber of the pump and impeller passage, while the multi-malfunction of the front wear-ring abrasion and back wear-ring abrasion has the most obvious effect on the flow velocity and flow stability inside pump. The pressure pulsation at Blade Passing Frequency (BPF) of the three schemes all decrease with the increase of the clearance.

scholarly journals Development of Depth-Limited Wave Boundary Layers over a Smooth Bottom

2020 ◽  
Vol 9 (1) ◽  
pp. 27
Author(s):  
Hitoshi Tanaka ◽  
Nguyen Xuan Tinh ◽  
Xiping Yu ◽  
Guangwei Liu
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Boundary Layers ◽  
Wave Motion ◽  
Numerical Study ◽  
Experiment Data ◽  
Tidal Motion ◽  
Long Period ◽  
Simulation Results ◽  
Wave Boundary

A theoretical and numerical study is carried out to investigate the transformation of the wave boundary layer from non-depth-limited (wave-like boundary layer) to depth-limited one (current-like boundary layer) over a smooth bottom. A long period of wave motion is not sufficient to induce depth-limited properties, although it has simply been assumed in various situations under long waves, such as tsunami and tidal currents. Four criteria are obtained theoretically for recognizing the inception of the depth-limited condition under waves. To validate the theoretical criteria, numerical simulation results using a turbulence model as well as laboratory experiment data are employed. In addition, typical field situations induced by tidal motion and tsunami are discussed to show the usefulness of the proposed criteria.

Design of Impeller of Centrifugal Compressor for Water-Air Engine

2014 ◽  
Vol 496-500 ◽  
pp. 642-645
Author(s):  
Yun Wang ◽  
Wei Zhang
Keyword(s):  
Numerical Simulation ◽  
Power System ◽  
Centrifugal Compressor ◽  
Centrifugal Impeller ◽  
3D Design ◽  
Pump Impeller ◽  
Aero Engine ◽  
Simulation Results

In view of power system in water-air UAV requirements, combine with the centrifugal impeller for aero-engine and the pump impeller. The design of a impeller of centrifugal compressor can work on the air and in the water for the new concept of air-water engine. With 3D design and a 3D CFD solver on it and analysis the results of numerical simulation. Results show that the designed impeller successfully reached the goal on the air and in the water. The experiences accumulated in this procedure are useful for similar impeller aerodynamic designs.

Sign in / Sign up

Export Citation Format

Share Document