The Design of a Corrugated Skin for the FishBAC Compliant Structure

2014 ◽  
Author(s):  
Iman Dayyani ◽  
Benjamin K. Woods ◽  
Michael I. Friswell
Keyword(s):  
Compliant Structure ◽  
Corrugated Skin

Compliant Bistable Dielectric Elastomer Actuators for Binary Mechatronic Systems

2005 ◽  
Author(s):  
Jean-Se´bastien Plante ◽  
Matthew Santer ◽  
Steven Dubowsky ◽  
Sergio Pellegrino
Keyword(s):  
Dielectric Elastomer ◽  
Mechatronic Systems ◽  
Flip Flop ◽  
Compliant Structure ◽  
Dielectric Elastomer Actuators

In this paper, a new all-polymer actuation approach for binary mechatronic systems is demonstrated. The technology consists of using Dielectric Elastomer actuators in a binary fashion by coupling them with a properly designed compliant structure. Here, a bistable actuator based around the “flip-flop” concept is implemented in which two antagonistic actuators switch a compliant truss between two stable positions. This prototype shows promising performance with output forces ranging from 1 to 3.5 N and displacements of 30% of the actuator dimension.

Comparative Evaluation of Foil Bearings With Different Compliant Structures for Improved Manufacturability

2017 ◽  
Author(s):  
K. Shalash ◽  
J. Schiffmann
Keyword(s):  
Cantilever Beam ◽  
Static Load ◽  
Measurement Tool ◽  
Reduced Order ◽  
Foil Bearings ◽  
Compliant Structure ◽  
Foil Bearing ◽  
Local Stiffness ◽  
Beam Foil ◽  
Bearing System

Potential geometrical deviations in bump foil bearings due to manufacturing uncertainty can have significant effects on both the local stiffness and clearance, and hence, affecting the overall bearing performance. The manufacturing uncertainty of bump type foil bearings was investigated, showing large geometrical deviations, using a developed measurement tool for the formed bump foils. A reduced order foil bearing model was used in a Monte Carlo simulation studying the effect of manufacturing noise on the onset of instability, highlighting the sensitivity of the rotor-bearing system to such manufacturing deviations. It was found that 30% of the simulated cases resulted improvements in stability, the remaining cases underperformed. Attempting to increase the robustness of the bearing, two other compliant structures replacing the classical gen-II bump foils were investigated from a manufacturing perspective. The first is a modified bump type Sinusoidal foil, and the second is the Cantilever beam foil. Consequently, quasi-static load-displacement tests were executed showing deviations in local clearance and stiffness for the classical bump type compliant structure compared to the other designs. It was found that the Cantilever beam foils yield more robustness compared to the bump type foils. Finally, an analytical model for the sequential engagement of the compliant structure is presented and validated with experimental measurements for both bump type and Cantilever structures.

Tolerance Induced Performance Variation of a High-Resolution Compliant Micro Stage

2007 ◽  
Author(s):  
Jhy-Cherng Tsai ◽  
Mandy Hsiao ◽  
Jau-Liang Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Resolution ◽  
Natural Frequency ◽  
Sensitivity Analyses ◽  
Compliant Structure ◽  
Nano Scale ◽  
Leaf Springs ◽  
Performance Variation ◽  
Element Method

Micro stage employs compliant structure is crucial for precision machinery as it can achieve nano-scale resolution fine displacement by deformation. This paper investigates the variations of stiffness and natural frequency due to dimensional tolerances of such a compliant micro stage that is suspended by four leaf springs and rotates with respect to hinges. Performances of the stage are evaluated by finite element method for various dimensions to investigate the effects of dimensions. A series of sensitivity analyses are also performed to investigate how tolerances affect the performance of the stage. It shows that the stiffness and natural frequency of the stage are strongly affected by the dimensions of leaf springs and the hinges. That is, tolerances of these dimensions are crucial and must be well designed and strictly controlled. It further shows that performance variation due to tolerances are nonlinear but can be properly designed with this approach.

scholarly journals Acutely ruptured basilar artery bifurcation aneurysm, treated with simultaneous Cascade and Comaneci temporary-assisted coiling

2020 ◽  
pp. neurintsurg-2020-016320
Author(s):  
Alexander Sirakov ◽  
Radoslav Raychev ◽  
Pervinder Bhogal ◽  
Stanimir Sirakov
Keyword(s):  
Basilar Artery ◽  
Coil Embolization ◽  
Cerebral Aneurysms ◽  
Content Type ◽  
Compliant Structure ◽  
Bifurcation Aneurysm ◽  
Vessel Patency ◽  
Endovascular Coil Embolization ◽  
Video Player ◽  
Temporary Stent

Temporary stent-assisted coiling is an eligible approach for the treatment of acutely ruptured complex cerebral aneurysms. Improved material properties and industrial advances in braiding technology have led to the introduction of new stent-like devices to augment endovascular coil embolization. Such technology includes the Cascade and Comaneci neck-bridging devices. Both devices are manually controlled, non-occlusive and fully retrievable neck-bridging temporary implants. The braided nature and the ultra-thin wire, compliant structure of their bridging meshes helps maintain target vessel patency during coil embolization. In this video (video 1) we demonstrate the straightforward combination of two temporary neck-bridging devices for the embolization of an acutely ruptured aneurysm of the basilar artery. Technical success and complete embolization of the aneurysm were recorded at the final angiography. In this technical video we discuss the technical nuances of the Comaneci and Cascade coil embolization.Video 1

Investigation of Structural Conformity in a Three-Pad Adaptive Air Foil Bearing With Regard to Active Control of Radial Clearance

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Hossein Sadri ◽  
Henning Schlums ◽  
Michael Sinapius
Keyword(s):  
Shape Control ◽  
Degrees Of Freedom ◽  
Load Capacity ◽  
Radial Clearance ◽  
Foil Bearings ◽  
Compliant Structure ◽  
Foil Bearing ◽  
Points Of View ◽  
Lift Off ◽  
Structural Conformity

Abstract Various solutions for the design of oil-free bearings are discussed in the literature. Adding hydrodynamic preload to the foil bearings by profiling the inner bore of the bearing is one of the most frequently investigated methods for improving the bearing stability and damping character of the entire system. However, this approach leads to a reduced load capacity and thus to an increased lift-off speed of the foil bearings. Observations of this kind lead to the presentation of various solutions for active bearing contour adjustment, which benefits from different profiles of the lubricant film. Most of these concepts use piezoelectric stack actuators to generate the required alternating force, although the influence of the stiffness of adaptive elements on bearing performance is not fully discussed in the literature. The focus of this study is on the investigation of structural conformity, i.e., the harmonization of stiffness with respect to the requirements for shape control and load capacity of an adaptive air foil bearing (AAFB). The result may be a basis for the consideration of additional degrees of freedom in any concept with shape control as the main design framework in interaction between the lubricant and compliant structure in an air foil bearing from both static and dynamic points of view.

Wrinkling of corrugated skin sandwich panels

2007 ◽  
Vol 38 (2) ◽  
pp. 576-589 ◽  
Author(s):  
Joachim L. Grenestedt ◽  
Jack Reany
Keyword(s):  
Sandwich Panels ◽  
Corrugated Skin

A Novel Motion Amplifier Using an Axially Driven Buckling Beam

Aerospace ◽  
2003 ◽  
Author(s):  
Jie Jiang ◽  
Eric M. Mockensturm
Keyword(s):  
Small Displacement ◽  
Compliant Structure ◽  
Euler’S Elastica ◽  
Large Rotations ◽  
Elastica Theory ◽  
End Conditions ◽  
Buckling Beam ◽  
Motion Amplifier ◽  
Piezoelectric Stacks ◽  
Measuring Instrumentation

For active materials such as piezoelectric stacks, which produce large force and small displacement, motion amplification mechanisms are often necessary—not simply to trade force for displacement, but to increase the output work transferred through a compliant structure. Here, a new concept for obtaining large rotations from small linear displacements produced by a piezoelectric stack is proposed and analyzed. The concept uses elastic (buckling) and dynamic instabilities of an axially driven buckling beam. The optimal design of the buckling beam end conditions was determined from a static analysis of the system using Euler’s elastica theory. This analysis was verified experimentally. A stack-driven, buckling beam prototype actuator consisting of a pre-compressed PZT stack (140 mm long, 10 mm diameter) and a thin steel beam (60 mm × 12 mm × 0.508 mm) was constructed. The buckling beam served as the motion amplifier, while the PZT stack provided the actuation. The experimental setup, measuring instrumentation and method, the beam preloading condition, and the excitation are fully described in the paper. Frequency responses of the system for three preloading levels and three stack driving amplitudes were obtained. A maximum 16° peak-to-peak rotation was measured when the stack was driven at an amplitude of 325 V and frequency of 39 Hz. The effects of beam preload were also studied.

Adaptive Heliostat Solar Arrays Using Shape-Optimized Compliant Mirrors

2012 ◽  
Author(s):  
Li Meng ◽  
Amy M. Bilton ◽  
Zheng You ◽  
Steven Dubowsky
Keyword(s):  
Structure Design ◽  
Two Dimensional ◽  
System Efficiency ◽  
Compliant Structure ◽  
Solar Arrays ◽  
Flat Mirror ◽  
Stiffness Profile ◽  
Solar Power Tower ◽  
Adjustment Mechanisms ◽  
The Ideal

In a Solar Power Tower (SPT) system, the ideal shape of a heliostat concentrator is a section of paraboloid which is a function of the location in the array and the incidence sun angle. This shape is difficult to achieve and limits the system efficiency. A shape-optimized compliant (SOC) design of parabolic heliostats is presented here to solve this problem. An approximation of the ideal shape is suggested to use an optimized stationary paraboloid shape which only varies with heliostat location in the array. A compliant structure design is proposed that to use a simple flat mirror with a two-dimensional tailored stiffness profile to form the required parabolic surface using adjustment mechanisms at each corner. This design is validated by numerical simulations including FEA tools, ray tracing, and classical nonlinear optimization. The annual performance shows that the SOC heliostat will substantially improve the efficiency and benefit the SPT system.

A sensor for measuring low frequency surface vibration of a fluid loaded compliant structure

1996 ◽  
Author(s):  
Alan D. McCleary ◽  
Patrick J. Klippel ◽  
A. Mark Young ◽  
D. H. Trivett
Keyword(s):  
Low Frequency ◽  
Surface Vibration ◽  
Compliant Structure
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