A Novel Approach for Designing Parabolic Mirrors Using Optimized Compliant Bands

2011 ◽  
Author(s):  
Lifang Li ◽  
Andres Kecskemethy ◽  
A. F. M. Arif ◽  
Steven Dubowsky
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Laboratory Experiments ◽  
Rear Surface ◽  
Energy Systems ◽  
Parabolic Trough ◽  
Element Analysis ◽  
Novel Approach ◽  
Flat Mirror ◽  
Flexible Metal

Parabolic concentrator mirrors are an important component of many solar energy systems, particularly solar mirror collectors. Precision parabolic mirrors are expensive to fabricate and to transport. Here, a new concept for designing and fabricating precision parabolic mirrors is presented. The mirror is formed from a thin flat very flexible metal sheet with a highly reflective surface. Attached to the rear surface of the mirror sheet is a backbone band whose figure is optimized to form the reflective sheet into a precision parabola when its two ends are pulled toward each other. An analytical model to optimize the shape of the band is presented. The validity of the concept is demonstrated using Finite Element Analysis and laboratory experiments. The concept would permit flat mirror elements to be easily fabricated and efficiently packaged and shipped to field sites and assembled into the parabolic trough concentrators with potentially substantial costs reductions compared with conventional methods.

Optimized Bands: A New Design Concept for Concentrating Solar Parabolic Mirrors

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Lifang Li ◽  
Andres Kecskemethy ◽  
A. F. M. Arif ◽  
Steven Dubowsky
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Solar Energy ◽  
Laboratory Experiments ◽  
Rear Surface ◽  
Energy Systems ◽  
Parabolic Trough ◽  
Element Analysis ◽  
Flat Mirror ◽  
Flexible Metal

Parabolic concentrator mirrors are an important component of many solar energy systems, particularly solar mirror collectors. Precision parabolic mirrors are expensive to fabricate and to transport. Here, a new concept for designing and fabricating precision parabolic mirrors is presented. The mirror is formed from a thin flat very flexible metal sheet with a highly reflective surface. Attached to the rear surface of the mirror sheet is a backbone band whose figure is optimized to form the reflective sheet into a precision parabola when its two ends are pulled toward each other. An analytical model to optimize the shape and thickness of the band is presented. The validity of the concept is demonstrated using Finite Element Analysis (FEA) and laboratory experiments. The concept would permit flat mirror elements to be easily fabricated and efficiently packaged and shipped to field sites and assembled into the parabolic trough concentrators with potentially substantial costs reductions compared with the conventional methods.

A Finite Element Analysis of Cold-Formed Z-Purlins Supported by Sandwich Panels

2013 ◽  
Vol 467 ◽  
pp. 398-403 ◽  
Author(s):  
Olga Tusnina
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Laboratory Experiments ◽  
Sandwich Panels ◽  
Element Model ◽  
Numerical Analyses ◽  
Scale Model ◽  
Element Analysis ◽  
Building Envelopes ◽  
Thin Walled

Nowadays buildings based on lightweight steel skeletons are widespread in civil and industrial engineering. The trapezoidal sheet or roof sandwich panels fastened to thin-walled cold-formed purlins can be used as the building envelopes. In this paper the questions of numerical analysis of thin-walled Z-purlins in the coverings made of sandwich panels are studied. Numerical analyses are performed in the program MSC.NASTRAN. A full scale model of the roof with purlins and sandwich panels is considered. Numerical analyses are based on the laboratory experiments. Results of described analyses are compared with the results of tests. These researches are done to investigate a behavior of the roof system consisted of Z-purlins and sandwich panels and to develop a correct finite element model for the design of cold-formed purlins supported by sandwich panels.

Design of a Parametrically Excited Tuning Fork Microgyroscope

2005 ◽  
Author(s):  
Yongsik Lee ◽  
Z. C. Feng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Analysis ◽  
Nonlinear Analysis ◽  
Tuning Fork ◽  
Simplified Model ◽  
Structure Parameters ◽  
Element Analysis ◽  
Parametrically Excited ◽  
Novel Approach

Parametrically excited tuning fork micro gyroscopes have several attractive features. Most of all, the excitation may be externalized, which could simplify the design and fabrication of micro gyroscopes. However, there are no readily applicable tools to guide the design of these gyroscopes since the gyro structures are more complex than those structures whose responses to parametric excitations are known and since finite element analysis tools are not capable of studying parametric excitations. In this work, we adopt a novel approach to obtain a simplified model of the parametrically excited structure. Parameters in the simplified model are obtained using dynamic analysis capability of typical finite element programs and static nonlinear analysis capabilities.

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