Energetics of a Circular Membrane Subjected to a Sudden Eccentric Circular Areal Constraint

2012 ◽  
Author(s):  
Assaad AlSahlani ◽  
Ranjan Mukherjee
Keyword(s):  
Total Energy ◽  
Active Control ◽  
Small Area ◽  
Outer Boundary ◽  
Maximum Energy ◽  
Energy Reduction ◽  
Physical Interaction ◽  
Circular Membrane ◽  
Time Of Application ◽  
Simulation Results

We investigate the energetics of a freely vibrating circular membrane subjected to a sudden eccentric circular areal constraint. The membrane is assumed to be fixed at its outer boundary and the constraint is assumed to be applied at an arbitrary time during the motion of the membrane. The constraint is applied instantaneously such that immediately after application of the constraint, the geometry of the membrane outside the area of the constraint remains unchanged and the constrained area comes to rest. The change in total energy after constraint application is investigated for different sizes and locations of the constraint and time of application of the constraint. The results show that the energy can decrease or increase depending on the time of application of the constraint. The condition for maximum energy reduction is presented and simulation results based on this condition show that sequential application and removal of the constraint reduces the total energy rapidly. This provides the opportunity for active control of membrane vibration through direct physical interaction with a small area of the membrane.

Suppression of String Vibration Using a Constraint Actuator at One Boundary

2010 ◽  
Author(s):  
Assaad AlSahlani ◽  
Ranjan Mukherjee
Keyword(s):  
Initial Conditions ◽  
Energy Content ◽  
Small Distance ◽  
Travel Distance ◽  
Physical Interaction ◽  
Time Of Application ◽  
String Vibration ◽  
Vibrating String ◽  
The Mean ◽  
Simulation Results

The problem of a vibrating string subjected to a sudden constraint at one boundary is investigated in this paper. The constraint is imposed by a sleeve that axially moves along the mean position of the string with a small distance. The constraint is applied instantaneously such that the geometry of the string outside the sleeve, immediately after application of the constraint, remains unchanged whereas the length of string covered by the sleeve remains at rest. The change in energy of the string after application and removal of the sleeve is investigated for different values of sleeve travel distance and time of application of the constraint. Analytical and numerical simulation results are first provided for the string vibrating in the first mode, and then for a more general case where the string has arbitrary initial conditions. The results show that the energy content can decrease or increase depending on the time of application of the constraint and sleeve travel distance. This provides the opportunity for active control of string vibration through direct physical interaction with a small portion of the string by using the sleeve as an actuator.

Research on Active Control for Thermal Deformation of Precise Membrane Reflector With Boundary SMA Actuators

2014 ◽  
Author(s):  
Yi-Fan Lu ◽  
Hong-Hao Yue ◽  
Zong-Quan Deng ◽  
Horn-Sen Tzou
Keyword(s):  
Active Control ◽  
Thermal Load ◽  
Membrane Structure ◽  
Shape Control ◽  
Membrane Surface ◽  
Circular Membrane ◽  
Equilibrium Equations ◽  
Large Space ◽  
Surface Accuracy ◽  
Thermal Disturbance

Along with the rapid development of space exploration, communication and earth observation technology, the large space membrane structure gains its widely application. With poor stiffness and large flexibility, the surface accuracy of membrane structures can be easily interfered by the space environment variety, so precise shape control of in-orbit space membrane reflector becomes the focus in space technology area. As an object for this paper, the active control of the membrane reflector deformation under typical thermal disturbance in space is investigated. Considering of Von-Karman geometrical nonlinearity, the equilibrium equations of a circular membrane are firstly presented based on Hamilton’s Principle and Love’s thin shell theory. As a simplification for equilibrium equations, the nonlinear mathematical model for the circular membrane in a symmetrical temperature field is obtained. In the next place, an FE model for a circular membrane under thermal load is developed in Abaqus as an example. By contrasting the FEM deformation analysis with mathematical modeling solutions of circular membrane reflectors under typical thermal load, it is demonstrated that the theoretical model is capable of predicting the amplitude of membrane surface deformation. At last, a boundary actuation strategy for membrane shape control is proposed, which could effectively decrease the membrane wrinkle induced by thermal disturbance via precisely control to the tension of the SMA wire actuators. The simulation result indicates the effectiveness of boundary active control strategy on improving membrane surface accuracy with different temperature distributions. The conclusions of modeling and analysis in this paper will be an essential theoretical foundation for future research on active flatness control for in-orbit large space membrane structure.

scholarly journals Investigating the Influence of Shaft Balance Point on Clubhead Speed: A Simulation Study

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 156
Author(s):  
William McNally ◽  
John McPhee
Keyword(s):  
Total Mass ◽  
Center Of Mass ◽  
Golf Club ◽  
Physical Interaction ◽  
Balance Point ◽  
Mass Distributions ◽  
Biomechanical Models ◽  
Significant Difference ◽  
The Mean ◽  
Simulation Results

In this study, a dynamic golfer model was used to investigate the influence of the golf shaft’s balance point (i.e., center of mass) on the generation of clubhead speed. Three hypothetical shaft designs having different mass distributions, but the same total mass and stiffness, were proposed. The golfer model was then stochastically optimized 100 times using each shaft. A statistically significant difference was found between the mean clubhead speeds at impact (p < 0.001), where the clubhead speed increased as the balance point moved closer to the grip. When comparing the two shafts with the largest difference in balance point, a 1.6% increase in mean clubhead speed was observed for a change in balance point of 18.8 cm. The simulation results have implications for shaft design and demonstrate the usefulness of biomechanical models for capturing the complex physical interaction between the golfer and golf club.

A Theoretical Basis for the Active Control of a Boring Bar Operation

1975 ◽  
Vol 97 (2) ◽  
pp. 172-178 ◽  
Author(s):  
R. G. Klein ◽  
C. L. Nachtigal
Keyword(s):  
Active Control ◽  
Theoretical Basis ◽  
Controller Design ◽  
Experimental System ◽  
Practical Consideration ◽  
Structural Damping ◽  
Boring Bar ◽  
Low Stiffness ◽  
Simulation Results ◽  
Using Data

The properties of low stiffness and low structural damping in boring bars are widely known to be factors resulting in chatter and inaccurate machining. The application of active control offers a new alternative to improving the performance of a boring bar. This paper presents the theoretical basis for such an active control system. The analysis includes the practical consideration of principal modes in the boring bar model and discusses this influence on controller design. Simulation results using data from an experimental system illustrate some important factors of system design.

scholarly journals Nonlinear active control of a cancerous tumour

2018 ◽  
Vol 7 (2.21) ◽  
pp. 72 ◽  
Author(s):  
Bhabani Shankar Dey ◽  
Manas Kumar Bera ◽  
Binoy Krishna Roy
Keyword(s):  
Active Control ◽  
Immune Cells ◽  
Normal Cell ◽  
Tumour Growth ◽  
Three Dimensional ◽  
Tumour Cells ◽  
Host Cells ◽  
Cancer Model ◽  
Control Objective ◽  
Simulation Results

This paper deals with the control of a cancerous tumour growth. The model used is a Three-Dimensional Cancer Model (TDCM). The competition terms include tumour cells, healthy cells, and immune cells. Nature of the competition among the populations of tumour cells, healthy host cells, and immune cells results in a chaotic behaviour. In this paper, a nonlinear active control has been used to control the growth of a tumour. Effect of chemotherapy drug on the different cell populations has been studied. Our control objective is to control the tumour growth and minimize its population to a small value which can be considered as harmless.Along with the above objective, the normal cell population is also be maintained at a particular level. This work has been done completely inin-sillico environment. The simulation results are shown extensively to support the theoretical analysis and confirmed that the preliminary objectives of the paper are attained.  

scholarly journals POTENSI PEMANFAATAN ATAP GEDUNG PUSAT PEMERINTAHAN KABUPATEN BADUNG UNTUK PLTS ROOFTOP

2018 ◽  
Vol 5 (2) ◽  
pp. 119
Author(s):  
I Dewa Gde Yaya Putra Pratama ◽  
I Nyoman Satya Kumara ◽  
I Nyoman Setiawan
Keyword(s):  
Total Energy ◽  
Electrical Power ◽  
Electrical Energy ◽  
South Side ◽  
North East ◽  
The North ◽  
North Side ◽  
Simulation Results ◽  
East West

In the RUPTL PT PLN Years 2017 untill 2026, the goverment aim to reach 5000 MW of PV plant potential in 2025. But, until November 2016, the number of PV plant in Indonesia is around 11 MW. To reach the 5000 MW target, many approach must be use. One of the approach is install PV plant on goverment buildings. Pusat Pemerintahan Kabupaten Badung (Puspem Badung) is a goverment buildings complex which located in Badung Regency, Bali is one of the goverment building that can be use for this approach. This paper aim to know the potency of electrical power dan electrical energy produced by Puspem Badung if the PV plant installed on the north, east, west, and south side of the roof. Electrical energy produced by PV plant is simulated by using System Advisor Model (SAM). From the simulation results, north side of the roof can produce energy of 1.847.361 kWh/year. From the analysis, the total energy that can be produced by PV plant is 6.169.092 kWh/year. This amount can supply Puspem Badung energy need by 124,72 %.

scholarly journals Detecting Boundary Nodes and Coverage Holes in Wireless Sensor Networks

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Li-Hui Zhao ◽  
Wenyi Liu ◽  
Haiwei Lei ◽  
Ruixia Zhang ◽  
Qiulin Tan
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Outer Boundary ◽  
Wireless Sensor ◽  
Special Events ◽  
Simulation Results ◽  
Novel Algorithms ◽  
Coverage Holes

The emergence of coverage holes in wireless sensor networks (WSNs) means that some special events have broken out and the function of WSNs will be seriously influenced. Therefore, the issues of coverage holes have attracted considerable attention. In this paper, we focus on the identification of boundary nodes and coverage holes, which is crucially important to preventing the enlargement of coverage holes and ensuring the transmission of data. We define the problem of coverage holes and propose two novel algorithms to identify the coverage holes in WSNs. The first algorithm, Distributed Sector Cover Scanning (DSCS), can be used to identify the nodes on hole borders and the outer boundary of WSNs. The second scheme, Directional Walk (DW), can locate the coverage holes based on the boundary nodes identified with DSCS. We implement the algorithms in various scenarios and fully evaluate their performance. The simulation results show that the boundary nodes can be accurately detected by DSCS and the holes enclosed by the detected boundary nodes can be identified by DW. The comparisons confirm that the proposed algorithms outperform the existing ones.

Active Control of a Circular Membrane to Reduce Transient Noise Transmission

1995 ◽  
Vol 117 (3A) ◽  
pp. 252-258 ◽  
Author(s):  
J. L. van Niekerk ◽  
B. H. Tongue
Keyword(s):  
Feedback Control ◽  
Active Control ◽  
Sliding Mode ◽  
Control Strategies ◽  
Circular Membrane ◽  
Velocity Feedback ◽  
Circular Duct ◽  
Control Approach ◽  
Noise Transmission

An active control approach that reduces transient noise transmission through a membrane in a circular duct is presented. Discrete sections of piezo-electrical film, PVDF, are used as actuators to adjust the tension of the membrane. Different control strategies, such as optimal, sliding mode and velocity feedback control, are investigated analytically and then implemented experimentally. It is shown that velocity feedback control is the more effective, stable controller for this application.

Optimization of inner and outer boundaries of beams and plates with holes

1981 ◽  
Vol 16 (4) ◽  
pp. 211-216 ◽  
Author(s):  
A J Durelli ◽  
K Rajaiah
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Small Area ◽  
Outer Boundary ◽  
Central Hole ◽  
Uniform Pressure ◽  
Two Dimensional ◽  
Photoelastic Method ◽  
Simply Supported ◽  
Square Plate

This paper presents optimized shapes of inner and outer boundaries for three specific problems: a long rectangular plate with a central hole subjected to uniaxial tension, a simply-supported slotted beam subjected to a load uniformly distributed over a small area at the centre, and a square plate with a central hole under uniaxial uniform pressure. The two-dimensional photoelastic method is used for optimization. The results indicate a significant reduction in stress concentration factor or in weight, or in both. The examples presented also include cases where the inner and outer boundary stresses are mutually dependent.

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