Vision-Based Sensing in Dynamic Tests

The availability of a suitable data acquisition sensor network is a key implementation issue to link models with real world structures. Non-contact displacement sensors should be preferred since they do not change the system properties. A two-dimensional vision-based displacement measurement sensor is the focus of this contribution. In particular, the perspective distortion introduced by the angle between the optic axis of the camera and the normal to the plane in which the structural system deforms is considered. A two-dimensional affine transformation is utilized to eliminate the distortion from the recorded to the distortion-free image. The results of a laboratory experiment show the potential of the proposed approach.

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Sub-Structure Pseudo-Dynamic Response Test of a Pseudo-Elastic Bracing System Made of Shape Memory Alloy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.297-300.628 ◽

2005 ◽

Vol 297-300 ◽

pp. 628-634 ◽

Cited By ~ 1

Author(s):

Kenichi Ohi ◽

Jae Hyouk Choi

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Original Position ◽

Small Displacement ◽

Structural System ◽

Dynamic Tests ◽

System A ◽

Hysteretic Damper ◽

Bracing System ◽

Fail Safe

This paper deals with shape memory alloy. As a first step to assess the applicability of this kind of alloy in a structural system, a tension bar made of this kind of alloy that exhibits pseudo-elasticity at room temperature is used herein as a passive bracing system. This paper describes sub-structure pseudo-dynamic tests on pseudo-elastic bracing system with hysteretic damper. A pseudo-elastic bracing system is better to be used with other hysteretic elements such as a hysteretic damper. A damper provides energy dissipation within small displacement levels, and a pseudo-elastic bracing system works in turn as a back-up/fail-safe system when an accidental failure of damper or damper interface occurs, and also it helps to pull back the structure to the original position by uninstalling the damper after earthquake.

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Two-dimensional barcodes: An effective real world example to teach design and programming

International Conference on Education and e-Learning Innovations ◽

10.1109/iceeli.2012.6360572 ◽

2012 ◽

Author(s):

Beena Ahmed ◽

Hossam Hammady

Keyword(s):

Real World ◽

Two Dimensional

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Recovery of Structural System Properties by Minimization of Finite Element Residuals Error Function

Trends in Applied Sciences Research ◽

10.3923/tasr.2011.672.685 ◽

2011 ◽

Vol 6 (7) ◽

pp. 672-685

Author(s):

Mohammed Arafa

Keyword(s):

Finite Element ◽

Error Function ◽

Structural System ◽

System Properties

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Harnessing tipping points in complex ecological networks

Journal of The Royal Society Interface ◽

10.1098/rsif.2019.0345 ◽

2019 ◽

Vol 16 (158) ◽

pp. 20190345 ◽

Cited By ~ 6

Author(s):

Junjie Jiang ◽

Alan Hastings ◽

Ying-Cheng Lai

Keyword(s):

Real World ◽

Management Strategy ◽

Ecological Networks ◽

Tipping Point ◽

Active Management ◽

Reduced Model ◽

Tipping Points ◽

Two Dimensional ◽

Pollinator Species ◽

Global Extinction

Complex and nonlinear ecological networks can exhibit a tipping point at which a transition to a global extinction state occurs. Using real-world mutualistic networks of pollinators and plants as prototypical systems and taking into account biological constraints, we develop an ecologically feasible strategy to manage/control the tipping point by maintaining the abundance of a particular pollinator species at a constant level, which essentially removes the hysteresis associated with a tipping point. If conditions are changing so as to approach a tipping point, the management strategy we describe can prevent sudden drastic changes. Additionally, if the system has already moved past a tipping point, we show that a full recovery can occur for reasonable parameter changes only if there is active management of abundance, again due essentially to removal of the hysteresis. This recovery point in the aftermath of a tipping point can be predicted by a universal, two-dimensional reduced model.

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Integrated Origami-String System

Volume 5B: 43rd Mechanisms and Robotics Conference ◽

10.1115/detc2019-97486 ◽

2019 ◽

Author(s):

Ke Liu ◽

Madelyn Kosednar ◽

Tomohiro Tachi ◽

Glaucio H. Paulino

Keyword(s):

Mechanical Behavior ◽

Design Space ◽

Energy Landscape ◽

Mechanical Systems ◽

Two Dimensional ◽

Structural System ◽

One Dimensional ◽

Elastic Strings ◽

Paper Folding

Abstract Origami-inspired mechanical systems are mostly composed of two-dimensional elements, a feature inherited from paper folding. However, do we have to comply with this restriction on our design space? Would it be more approachable to achieve desired performance by integrating elements of different abstract dimensions? In this paper, we propose an integrated structural system consisting of both two-dimensional and one-dimensional elements. We attach elastic strings onto an origami design to modify its mechanical behavior and create new features. We show that, by introducing elastic strings to the recently proposed Morph pattern, we can obtain bistable units with programmable energy landscape. The behavior of this integrated origami-string system can be described by an elegant formulation, which can be used to explore its rich programmability.

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