Shape Optimization of a Compliant Mechanism for an Actively Conformable Rotor Airfoil

2004 ◽  
Author(s):  
Andrew Nissly ◽  
Phuriwat Anusonti-Inthra ◽  
Mary Frecker ◽  
Farhan Gandhi
Keyword(s):  
Shape Optimization ◽  
Cross Section ◽  
Strain Energy ◽  
Rotation Angle ◽  
Compliant Mechanism ◽  
Aerodynamic Loads ◽  
Optimal Geometry ◽  
Uniform Cross Section ◽  
Narrow Space ◽  
Actuation Strain

In the present study, the optimal shape of a limited amount of passive material in a compliant mechanism of predetermined topology was determined. The simple compliant mechanism with a small number of actuators can be packaged in the long, narrow space of the rotor airfoil cross-section. The compliant mechanism is designed for maximum rotation angle under actuation loads, and minimum deflection under aerodynamic loads. Rotation angle (RA) and Strain Energy (SE), are used as measures of the deflections created by the actuation and aerodynamic loads, respectively. The design objectives are achieved by maximizing a multi-criteria objective function that represents a ratio of the RA to SE. Shape optimization of the compliant mechanism is conducted and the results indicate that the optimal compliant mechanism consists of a passive substructure with uniform cross section. The optimal geometry of the compliant mechanism is also determined in a parametric study (optimal ratio of the length to height of 0.3), and this structure can produce rotation angle of 13 Deg/m. when the actuators provide 1% actuation strain. The deflection due to aerodynamic loads is extremely small. The performance of the mechanism is examined further with variations in material and actuator properties. Additional results include an analysis of a compliant mechanism structure based on a modified topology, which is introduced to reduce numbers of actuators.

Enhancement of quasi-static strain energy harvesters using non-uniform cross-section post-buckled beams

2017 ◽  
Vol 26 (8) ◽  
pp. 085045 ◽  
Author(s):  
Pengcheng Jiao ◽  
Wassim Borchani ◽  
Hassene Hasni ◽  
Nizar Lajnef
Keyword(s):  
Cross Section ◽  
Strain Energy ◽  
Static Strain ◽  
Energy Harvesters ◽  
Buckled Beams ◽  
Uniform Cross Section

The Stress Analysis of the Circular Conical Fuselage with Flexible Frames

1955 ◽  
Vol 59 (536) ◽  
pp. 527-550
Author(s):  
W. J Goodey
Keyword(s):  
Stress Analysis ◽  
Cross Section ◽  
Cross Sections ◽  
Strain Energy ◽  
Circular Cross Section ◽  
Arbitrary Distribution ◽  
Skin Thickness ◽  
Complex Type ◽  
Uniform Cross Section ◽  
Minimum Strain Energy

Summary:This paper is concerned with the problem of the skin–and–stringer–covered conical fuselage of circular cross section, having flexible frames and being subjected to an arbitrary distribution of loads applied in the planes of these frames or on the end cross sections. The skin thickness and stringer cross section may vary from bay to bay but are assumed to be constant in a bay, i.e. between any two consecutive frames. The stringers are assumed to be uniformly spaced round the circumference. The frames are assumed to be of uniform cross section (circumferentially) but their stiffnesses are arbitrary, as is also their spacing along the fuselage.This paper is a sequel to one previously published in the Journal, but the method of analysis is now by minimum strain energy instead of by deflections. Owing to the generality of the investigation it is impossible to present the solution—in terms of the known loads and stiffnesses—in any explicit form, and attention has therefore been concentrated on the technique of numerical computation. A scheme of tabulation has been evolved, and its use is illustrated by a fully–worked numerical example of a moderately complex type.

Oxidation of Suspended Stacked Silicon Nanowire for Sub-10nm Cross-Section Shape Optimization

2019 ◽  
Vol 13 (1) ◽  
pp. 195-199 ◽  
Author(s):  
Alexandre Hubert ◽  
Jean-Philippe Colonna ◽  
Stéphane Bécu ◽  
Cécilia Dupré ◽  
Virginie Maffini-Alvaro ◽  
...  
Keyword(s):  
Shape Optimization ◽  
Cross Section ◽  
Silicon Nanowire ◽  
Cross Section Shape ◽  
Section Shape

The Use of Strain Energy and Fracture Correlation to Determine Life Expectancy for Notched Components

2009 ◽  
Author(s):  
Onome Scott-Emuakpor ◽  
Tommy George ◽  
Charles Cross ◽  
M.-H. Herman Shen
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Cross Section ◽  
Strain Energy ◽  
Notch Root ◽  
Stress Gradient ◽  
Strain Curve ◽  
Experimental Results ◽  
Cyclic Process ◽  
Notched Components

An energy-based method for predicting fatigue life of half-circle notched specimens, based on the nominal applied stress amplitude, has been developed. This developed method is based on the understanding that the total strain energy dissipated during a monotonic fracture and a cyclic process is the same material property, where the density of each can be determined by measuring the area underneath the monotonic true stress-strain curve and measuring the sum of the area within each Hysteresis loop in the cyclic process, respectively. Using this understanding, the criterion for determining fatigue life prediction of half-circle notched components is constructed by incorporating the stress gradient effect through the notch root cross-section. Though fatigue at a notch root is a local phenomenon, evaluation of the stress gradient through the notch root cross-section is essential for incorporating this method into finite element analysis minimum potential energy process. The validation of this method was carried out by comparison with both notched and unnnotched experimental fatigue life of Aluminum 6061-T6 (Al 6061-T6) specimens under tension/compression loading at the theoretical notch fatigue stress concentration factor of 1.75. The comparison initially showed a slight deviation between prediction and experimental results. This led to the analysis of strain energy density per cycle up to failure, and an improved Hysteresis representation for the energy-based prediction analysis. With the newly developed Hysteresis representation, the energy-based prediction comparison shows encouraging agreement with unnotched experimental results and a theoretical notch stress concentration value.

A STUDY ON THE SQUEAL OF A DRUM BRAKE WHICH HAS SHOES OF NON-UNIFORM CROSS-SECTION

2001 ◽  
Vol 240 (5) ◽  
pp. 789-808 ◽  
Author(s):  
J.M. LEE ◽  
S.W. YOO ◽  
J.H. KIM ◽  
C.G. AHN
Keyword(s):  
Cross Section ◽  
Drum Brake ◽  
Uniform Cross Section

Deflection of Beams of Varying Cross Section

1937 ◽  
Vol 4 (2) ◽  
pp. A49-A52
Author(s):  
Miklós Hetényi
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Original Problem ◽  
New Method ◽  
Constant Cross Section ◽  
Deflection Curve ◽  
Force System ◽  
Uniform Cross Section ◽  
The Cross

Abstract This paper calls attention to a new method of dealing with deflections of beams, the cross sections of which vary by steps. It is shown that the effect of this variation on the shape of the deflection curve can be represented by a properly chosen force system acting on a beam of uniform cross section. There is no approximation involved in this substitution, whereby the original problem is reduced to one of computing deflections of beams of constant cross section.

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