Micro-Electromechanics of Sensor Patches of Free Paraboloidal Shell Structronic Systems

2002 ◽  
Author(s):  
J. H. Ding ◽  
H. S. Tzou
Keyword(s):  
Shape Control ◽  
Distributed Sensing ◽  
Signal Generation ◽  
Shell Structures ◽  
Shells Of Revolution ◽  
Distributed Sensors ◽  
Free Boundary Conditions ◽  
Parametric Studies ◽  
Paraboloidal Shell ◽  
Sensing Characteristics

Distributed sensing of structural states is essential to vibration control, health monitoring and shape control of precision structronic systems. Paraboloidal shells of revolution are widely used in aerospace, telecommunication, etc. structures. However, distributed sensing of paraboloidal shell structures is rarely investigated over the years. Micro-sensing characteristics, sensor segmentation, sensor placements, shell geometric parameters, etc. of deep/shallow paraboloidal shells are evaluated in this study. Signal generation of generic distributed sensors laminated on paraboloidal shells is defined; microscopic signal components of segmented sensor patches laminated on deep/shallow paraboloidal shells with free boundary conditions are analyzed. Parametric studies of microelectromechanics and microscopic signal generations of segmented sensor patches reveal detailed modal sensing signal generation and efficiency of segmented sensor patches laminated at various shell locations of three paraboloidal shells (i.e., a shallow, a standard, and a deep).

Micro-Control Actions of Segmented Actuators on Shallow Paraboloidal Shell Reflectors

2002 ◽  
Author(s):  
S.-S. Lih ◽  
G. Hickey ◽  
J. H. Ding ◽  
H. S. Tzou
Keyword(s):  
Distributed Control ◽  
Design Guidelines ◽  
Shell Structures ◽  
Natural Mode ◽  
Shells Of Revolution ◽  
Control Effect ◽  
Control Cost ◽  
Control Actions ◽  
Control Forces ◽  
Paraboloidal Shell

Shallow paraboloidal shells of revolution are common components for reflectors, mirrors, etc. This study is to investigate the micro-control actions and distributed control effectiveness of precision paraboloidal shell structures laminated with segmented actuator patches. Mathematical models and governing equations of the paraboloidal shells laminated with distributed actuator layers segmented into patches are presented first, followed by formulations of distributed control forces and micro-control actions including meridional/circumferential membrane and bending control components based on an assumed mode shape function and the Taylor series expansion. Distributed control forces, patch sizes, actuator locations, micro-control actions, and normalized control authorities of a shallow paraboloidal shell are then analyzed in a case study. Analysis indicates that 1) the control forces and membrane/bending components are mode and location dependent, 2) the meridional/circumferential membrane control actions dominate the overall control effect, 3) there are optimal actuator locations resulting in the maximal control effects at the minimal control cost for each natural mode. The analytical results provide generic design guidelines for actuator placement on precision shallow paraboloidal shell structures.

Distributed Modal Voltages of Nonlinear Paraboloidal Shells With Distributed Neurons

2004 ◽  
Vol 126 (1) ◽  
pp. 47-53 ◽  
Author(s):  
H. S. Tzou ◽  
J. H. Ding
Keyword(s):  
Dynamic Responses ◽  
Dynamic State ◽  
Structural Components ◽  
Shells Of Revolution ◽  
Membrane Component ◽  
Fully Integrated ◽  
In Situ Sensors ◽  
Membrane Components ◽  
Paraboloidal Shell

Effective health monitoring and distributed control of advanced structures depends on accurate measurements of dynamic responses of elastic structures. Conventional sensors used for structural measurement are usually add-on “discrete” devices. Lightweight distributed thin-film piezoelectric neurons fully integrated (laminated or embedded) with structural components can serve as in-situ sensors monitoring structure’s dynamic state and health status. This study is to investigate modal voltages and detailed signal contributions of linear or nonlinear paraboloidal shells of revolution laminated with piezoelectric neurons. Signal generation of distributed neuron sensors laminated on paraboloidal shells is defined first, based on the open-voltage assumption and Maxwell’s principle. The neuron signal of a linear paraboloidal shell is composed of a linear membrane component and a linear bending component; the signal of a nonlinear paraboloidal shell is composed of nonlinear and linear membrane components and a linear bending component due to the von Karman geometric nonlinearity. Signal components and distributed modal voltages of linear and nonlinear paraboloidal shells with various curvatures and thickness are investigated.

PdPt bimetallic nanoparticles enabled by shape control with halide ions and their enhanced catalytic activities

Nanoscale ◽  
2016 ◽  
Vol 8 (7) ◽  
pp. 3962-3972 ◽  
Author(s):  
Jinfeng Zhang ◽  
Lei Wan ◽  
Lei Liu ◽  
Yida Deng ◽  
Cheng Zhong ◽  
...  
Keyword(s):  
Shape Control ◽  
Bimetallic Nanoparticles ◽  
Shell Structures ◽  
Core Shell ◽  
Halide Ions ◽  
Catalytic Activities

The morphologies of PdPt nanoparticles with various core–shell structures could be controlled by altering the participation of different halide ions.

Micro-Signals and Modal Potentials of Nonlinear Deep and Shallow Conical Shells

2002 ◽  
Author(s):  
W. K. Chai ◽  
P. Smithmaitrie ◽  
H. S. Tzou
Keyword(s):  
Smart Materials ◽  
Conical Shell ◽  
Polyvinylidene Fluoride ◽  
Flexible Structures ◽  
Distributed Sensing ◽  
Shell Structures ◽  
Dynamic State ◽  
Toroidal Shell ◽  
Strain Component ◽  
Conical Shells

Conventional sensors, such as proximeters and accelerometers, are add-on devices usually adding additional weights to structures and machines. Health monitoring of flexible structures by electroactive smart materials has been investigated over the years. Thin-film piezoelectric material, e.g., polyvinylidene fluoride (PVDF) polymeric material, is a lightweight and dynamic sensitive material appearing to be a perfect candidate in monitoring structure’s dynamic state and health status of flexible shell structures with complex geometries. The complexity of shell structures has thwarted the progress in studying the distributed sensing of shell structures. Linear distributed sensing of various structures have been studied, like beam, plate, cylindrical shell, conical shell, spherical shell, paraboloidal shell and toroidal shell. However, distributed sensing control of nonlinear shell structures has not been carried out rigorously. This study is to present the microscopic signals, modal voltages and distributed micro-sensing components of truncated nonlinear conical shells laminated with distributed infinitesimal piezoelectric neurons. Signal generation of distributed neuron sensors laminated on conical shells is defined first. The dynamic signal of truncated nonlinear conical shell consists of microscopic linear and nonlinear membrane strain components and linear bending strain component based on the von Karman geometric nonlinearity. Micro-signals, modal voltages and distributed sensing components of two different truncated nonlinear conical shells are investigated and their sensitivities discussed.

scholarly journals THE WAVE PROCESSES IN THREE-LAYER SHELLS OF ROTATIONWITH TAKING INTO ACCOUNT THE DISCRETE FILLER AT NON-STATIONARY LOADS

2020 ◽  
Author(s):  
Vladimyr Meish ◽  
◽  
Yuliia Meish ◽  
Keyword(s):  
Numerical Method ◽  
Strain State ◽  
Shell Structures ◽  
Sharp Change ◽  
Space Technology ◽  
Shells Of Revolution ◽  
Stress Strain ◽  
Shell Elements ◽  
Stress Strain State ◽  
Explicit Finite Difference

Thin-walled shell structures in the form of plates and shells of various shapes have a high bearing capacity, lightness, and relative ease of manufacture. Three-layer shell elements, which consist of two bearing layers and a filler, which ensures their joint work, are widely used in mechanical engineering, industrial and civil construction, aviation and space technology, shipbuilding. When calculating the strength of three-layer shell structures with a discrete filler under dynamic loads, it becomes necessary to determine the stress-strain state both in the area of a sharp change in the geometry of the structure and at a considerable distance from the heterogeneity. The complexity of the processes that arise in this case necessitates the use of modern numerical methods for solving dynamic problems of the behavior of three-layer shell elements with a discrete filler. In this regard, the determination of the stress-strain state of three-layer shells with a discrete filler under non-stationary loads and the development of an effective numerical method for solving problems of this class is an urgent problem in the mechanics of a deformable solid. On the basis of the theory of threelayered shells with applying the hypotheses for each layer the nonstationary vibrations threelayered shells of revolution with allowance of discrete fillers are investigated. Hamilton-Ostrogradskyy variational principle for dynamical processes is used for deduction of the motion equations. An efficient numerical method for solution of problems on nonstationary behaviour of threelayers shells of revolution with allowance of discrete fillers are used. The wide diapason of geometrical, and physico-mechanical parameters of nonhomohenes threelayered structure are considerated. On the basis of the offered model nonstationary problems of the forced nonlinear vibrations of threelayered shells of revolution of various structure are solved and analysed. The basis of the developed numerical method for the study of nonstationary oscillations is the application of explicit finite-difference schemes to solve the initial differential equations in partial derivatives. The theory is based on the relations of the theory of three-layer shells of revolution taking into account the discreteness of the filler, which are based on the hypotheses of the geometrically nonlinear theory of shells and rods of the Timoshenko type.

Spatially Distributed Signals of Nonlinear Paraboloidal Shells With Distributed Neurons

2001 ◽  
Author(s):  
H. S. Tzou ◽  
J. H. Ding
Keyword(s):  
Dynamic Responses ◽  
Dynamic State ◽  
Structural Components ◽  
Shells Of Revolution ◽  
Fully Integrated ◽  
Spatially Distributed ◽  
In Situ Sensors ◽  
Membrane Components ◽  
Paraboloidal Shell

Abstract Effective health monitoring and distributed control of advanced structures depends on accurate measurements of dynamic responses of elastic structures. Conventional sensors used for structural measurement are usually add-on “discrete” devices. Lightweight distributed thin-film piezoelectric neurons fully integrated (laminated or embedded) with structural components can serve as in-situ sensors monitoring structure’s dynamic state and health status. This study is to investigate modal voltages and detailed signal contributions of linear or nonlinear paraboloidal shells of revolution laminated with piezoelectric neurons. Signal generation of distributed neuron sensors laminated on paraboloidal shells is defined first, based on the open-voltage assumption and Maxwell’s principle. The neuron signal of a linear paraboloidal shell is composed of a linear membrane component and a linear bending component; the signal of a nonlinear paraboloidal shell governed by the von Karman geometric nonlinearity is composed of nonlinear and linear membrane components and a linear bending component. Signal components and distributed modal voltages of linear and nonlinear paraboloidal shells with various curvatures and thickness are investigated.

Optimal Feedback Control of Precision Paraboloidal Shell Structronic Systems

2002 ◽  
Author(s):  
H. S. Tzou ◽  
J. H. Ding
Keyword(s):  
Feedback Control ◽  
Elastic Shell ◽  
State Feedback Control ◽  
Optimal Feedback Control ◽  
External Control ◽  
Shell Shape ◽  
Linear Quadratic ◽  
Sensors And Actuators ◽  
Distributed Sensors ◽  
Paraboloidal Shell

Paraboloidal shell of revolution is a common shell shape used in aerospace, telecommunication, dome structures and many other engineering applications. A structronic shell system is defined as an elastic shell bonded or laminated with piezoelectric sensors and actuators and it is governed by either in-situ or external control electronics. A closed-loop control system of paraboloidal shell structronic system consists of distributed sensors/actuators and controller coupled with the elastic paraboloidal shell. State equation for the paraboloidal shell structronic system is derived and optimal linear quadratic (LQ) state feedback control is implemented, such that the “best” shell control performance with the least control costs can be achieved. The gain matrix is estimated based on minimizing a performance criterion function. Optimal control effects are compared with controlled responses with other non-optimal PD control parameters. Control effects of sensor/actuator patches at different locations with same size are studied and compared; control effects for different natural modes are also investigated.

scholarly journals BUGS ON A BUDGET: DISTRIBUTED SENSING WITH COST FOR REPORTING AND NONREPORTING

2010 ◽  
Vol 24 (4) ◽  
pp. 525-534 ◽  
Author(s):  
Vladimir Pozdnyakov ◽  
J. Michael Steele
Keyword(s):  
Random Walk ◽  
Simple Model ◽  
Explicit Formula ◽  
Distributed Sensing ◽  
Sequential Decisions ◽  
Distributed Sensors ◽  
Fixed Budget ◽  
The Relationship ◽  
Ruin Problem

We consider a simple model of sequential decisions made by a fusion agent that receives binary-passive reports from distributed sensors. The main result is an explicit formula for the probability of making a decision before a fixed budget is exhausted. These results depend on the relationship between a special ruin problem for a “lazy random walk” and a traditional biased walk.

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