Bistability in Cylindrical Developable Mechanisms Through the Principle of Reflection

2021 ◽  
Vol 143 (8) ◽  
Author(s):  
Jared Butler ◽  
Jacob Greenwood ◽  
Larry L. Howell ◽  
Spencer Magleby
Keyword(s):  
Numerical Simulation ◽  
Mechanism Design ◽  
Surface Analysis ◽  
Cylindrical Surface ◽  
Necessary Conditions ◽  
Graphical Method ◽  
Design Tools ◽  
Torsional Spring

Abstract We present a resource for designing bistable developable mechanisms (BDMs) that reach their second stable positions while exterior or interior to a cylindrical surface. Analysis of the necessary conditions to create extramobile and intramobile cylindrical BDMs is conducted through a series of three tests. These tests contain elements of both existing and new mechanism design tools, including a novel graphical method for identifying stable positions of linkages using a single dominant torsional spring, called the principle of reflection. These tests are applied to all possible mechanism cases and configurations to identify why certain configurations will always, sometimes, or never be a BDM. Two tables summarize these results as a guide when designing extramobile and intramobile BDMs. The results are compared and demonstrated with a numerical simulation of 30,000+ mechanisms, including several example mechanisms that illustrate the concepts discussed in the work. Discussion is then provided on the implication of these results.

Bistable Compliant Four-Bar Mechanisms With a Single Torsional Spring

2006 ◽  
Author(s):  
Adarsh Mavanthoor ◽  
Ashok Midha
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanism Design ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Stored Energy ◽  
Element Analysis ◽  
Bistable Behavior ◽  
Torsional Spring ◽  
Bistable Mechanism

Significant reduction in cost and time of bistable mechanism design can be achieved by understanding their bistable behavior. This paper presents bistable compliant mechanisms whose pseudo-rigid-body models (PRBM) are four-bar mechanisms with a torsional spring. Stable and unstable equilibrium positions are calculated for such four-bar mechanisms, defining their bistable behavior for all possible permutations of torsional spring locations. Finite Element Analysis (FEA) and simulation is used to illustrate the bistable behavior of a compliant mechanism with a straight compliant member, using stored energy plots. These results, along with the four-bar and the compliant mechanism information, can then be used to design a bistable compliant mechanism to meet specified requirements.

Quantitative Risk Analysis for Natural Gas Long-Distance Pipeline Leakage

2014 ◽  
Vol 1030-1032 ◽  
pp. 661-664
Author(s):  
Zhe Zuo
Keyword(s):  
Numerical Simulation ◽  
Risk Assessment ◽  
Natural Gas ◽  
Emergency Response ◽  
Necessary Conditions ◽  
Quantitative Risk Assessment ◽  
Safe Operation ◽  
Long Distance ◽  
Main Factors ◽  
Accident Scenarios

The risk of natural gas long-distance pipeline and main factors of accidents are analyzed in this paper. According the consequences from above, quantitative risk assessment of long-distance pipelines under specific accident scenarios are completed with the help of numerical simulation model on long-distance pipeline leakage and dispersion. What’s more, on the basis of the assessment results, the necessary conditions for long-distance pipeline safe operation are presented. Finally, conclusions and safe operations under necessary conditions given in this paper are helpful for regular operation of pipeline, accident prevention, emergency response and reasonable supervision.

Water uptake by substituted amylose tablets: experimentation and numerical simulation

2009 ◽  
Vol 00 (00) ◽  
pp. 090904073309027-8
Author(s):  
H.W. Wang ◽  
S. Kyriacos ◽  
L. Cartilier
Keyword(s):  
Numerical Simulation ◽  
Water Uptake

Relation of Statistically Significant, Abnormal, and Typical WAIS-R VIQ-PIQ Discrepancies to Full Scale IQs

2000 ◽  
Vol 16 (2) ◽  
pp. 107-114 ◽  
Author(s):  
Louis M. Hsu ◽  
Judy Hayman ◽  
Judith Koch ◽  
Debbie Mandell
Keyword(s):  
Graphical Method ◽  
The United States ◽  
Full Scale ◽  
True Score ◽  
Absolute Value ◽  
Normative Population ◽  
The Us ◽  
The Mean ◽  
And Performance ◽  
Quadratic Models

Summary: In the United States' normative population for the WAIS-R, differences (Ds) between persons' verbal and performance IQs (VIQs and PIQs) tend to increase with an increase in full scale IQs (FSIQs). This suggests that norm-referenced interpretations of Ds should take FSIQs into account. Two new graphs are presented to facilitate this type of interpretation. One of these graphs estimates the mean of absolute values of D (called typical D) at each FSIQ level of the US normative population. The other graph estimates the absolute value of D that is exceeded only 5% of the time (called abnormal D) at each FSIQ level of this population. A graph for the identification of conventional “statistically significant Ds” (also called “reliable Ds”) is also presented. A reliable D is defined in the context of classical true score theory as an absolute D that is unlikely (p < .05) to be exceeded by a person whose true VIQ and PIQ are equal. As conventionally defined reliable Ds do not depend on the FSIQ. The graphs of typical and abnormal Ds are based on quadratic models of the relation of sizes of Ds to FSIQs. These models are generalizations of models described in Hsu (1996) . The new graphical method of identifying Abnormal Ds is compared to the conventional Payne-Jones method of identifying these Ds. Implications of the three juxtaposed graphs for the interpretation of VIQ-PIQ differences are discussed.

Soldier-Centered Design Tools: Recent Developments, Challenges, and Paths Forward

2005 ◽  
Author(s):  
John K. Hawley ◽  
John F. Lockett ◽  
Laurel E. Allender
Keyword(s):  
Design Tools ◽  
Recent Developments
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