An Elastomeric Ejection System

1994 ◽  
Vol 67 (5) ◽  
pp. 892-903 ◽  
Author(s):  
I. S. Choi ◽  
C. M. Roland ◽  
L. C. Bissonnette
Keyword(s):  
Fatigue Life ◽  
Elastic Energy ◽  
Material Properties ◽  
The U.S ◽  
Selection Of

Abstract The ability of elastomers to store large quantities of energy, which can subsequently be recovered very quickly, makes them attractive materials for propulsion devices. Recently the U.S. Navy has developed a torpedo ejection system based on an elastomeric mechanical capacitor. The criteria governing selection of a material for this application include high elastic energy, sufficient fatigue life, minimal creep, and resistance to deterioration by seawater. This paper describes various approaches to obtaining these material properties.

Influence of Wear Properties on Fretting Fatigue Life of a CK45 Alloy and the Al7175 Alloy

2008 ◽  
Vol 587-588 ◽  
pp. 971-975 ◽  
Author(s):  
M. Buciumeanu ◽  
A.S. Miranda ◽  
F.S. Silva
Keyword(s):  
Wear Resistance ◽  
Fatigue Life ◽  
Material Properties ◽  
Fatigue Behavior ◽  
Synergetic Effect ◽  
Fretting Fatigue ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Wear Properties

The main objective of this work was to study the influence of the wear properties of two commercial alloys (CK45 and Al7175) on their fretting fatigue behavior. It is verified the effect of material local degradation by wear on a fatigue strength reduction factor, namely the stress concentration factor, and on the overall fretting fatigue life of these materials. The fretting fatigue phenomenon is a synergetic effect between wear and fatigue. It is dependent on both the fatigue and the wear properties of the materials. Material properties promoting an increase in wear resistance should enhance fretting fatigue life.

A new representation for a robot grasping quality measure

Robotica ◽  
1995 ◽  
Vol 13 (3) ◽  
pp. 287-295 ◽  
Author(s):  
Venugopal K. Varma ◽  
Uri Tasch
Keyword(s):  
Objective Function ◽  
Material Properties ◽  
Graphical Representation ◽  
Contact Forces ◽  
Geometric Constraints ◽  
Objective Functions ◽  
Finger Force ◽  
Finger Forces ◽  
Robot Grasping ◽  
Selection Of

SummaryWhen an object is held by a multi-fingered hand, the values of the contact forces can be multivalued. An objective function, when used in conjunction with the frictional and geometric constraints of the grasp, can however, give a unique set of finger force values. The selection of the objective function in determining the finger forces is dependent on the type of grasp required, the material properties of the object, and the limitations of the röbot fingers. In this paper several optimization functions are studied and their merits highlighted. The paper introduces a graphical representation of the finger force values and the objective functions that enable one to select and compare various grasping configurations. The impending motion of the object at different torque and finger force values are determined by observing the normalized coefficient of friction plots.

scholarly journals United States : Good Ideas from Successful Cities : Regional Snapshots in Comparative Perspective

2021 ◽  
Author(s):  
Kim Turner
Keyword(s):  
United States ◽  
The United States ◽  
Immigrant Integration ◽  
Comparative Perspective ◽  
The U.S ◽  
Selection Of

<div>Our main report, Good Ideas from Successful Cities: Municipal Leadership in Immigrant Integration, explores these themes through a selection of nearly 40 profiles of municipal practice and policies from cities across Canada, the U.S., Europe and Australasia. In this companion report, United States: Good Ideas from Successful Cities, we present an additional snapshot of municipal leadership and excellence in immigrant integration from cities in the United States. Each of these five city profiles includes a selection of related international city practices to encourage comparative perspective and enriched learning.</div>

The T-AGS-39 Class Ocean Survey Ships and Their Conversion to Schoolships

2002 ◽  
Vol 39 (03) ◽  
pp. 170-186
Author(s):  
John C. Daidola ◽  
Robert S. Behr ◽  
John G. Lynch ◽  
Erhard W. Koehler
Keyword(s):  
Original Design ◽  
Insight Into ◽  
The U.S ◽  
Selection Of ◽  
Design Construction ◽  
Naval Service

Elements of the design, construction and later conversion of the T-AGS-39 Class Ocean Survey Ships are reviewed. The original design to a U.S. Navy Circular of Requirements is considered, presenting insight into the selection of vessel characteristics. The construction program, in concert with unique requirements, is also considered. Finally, conversion of the vessels to schoolships under the U.S. Maritime Administration, following their retirement from naval service, is discussed.

The Mexican Government and Repatriation, November 1934–June 1936

2017 ◽  
Author(s):  
Alanís Enciso Fernando Saúl ◽  
Russ Davidson
Keyword(s):  
Baja California ◽  
Mexican Migrants ◽  
Mexican Government ◽  
The Cost ◽  
Strict Selection ◽  
The U.S ◽  
Selection Of ◽  
Agricultural Labourers

This chapter discusses the Cardenista government’s attempt to find a solution to the foreseen threat of a mass return of Mexican migrants from the U.S. Chapter 3 details how the Cardenas administration established that only a strict selection of skilled agricultural labourers would be permitted to return, and details how the administration determined that individual Mexican states should accept responsibility for providing both housing and assistance for repatriated nationals. Drawing on an overview of the studies conducted by the Cardenas administration on the population of Mexican nationals living in the U.S., this chapter states that ultimately, it was proposed that 450,000 people could be resettled at the cost of 366,345,291 pesos, and that this figure was well outside the government’s budget. Lastly, this chapter notes that plans for a resettlement colony in Baja California- called “Mexico Libre”- were established but never came to fruition.

A Simulation Method of Establishing Fatigue Life Distribution

1976 ◽  
Vol 98 (1) ◽  
pp. 183-188 ◽  
Author(s):  
H. A. Elmaraghy ◽  
J. N. Siddall
Keyword(s):  
Fatigue Life ◽  
Material Properties ◽  
Digital Simulation ◽  
Simulation Method ◽  
Fatigue Tests ◽  
Design Tool ◽  
Statistical Characteristics ◽  
Life Distribution ◽  
Parametric Studies ◽  
Life Distributions

This paper presents a Monte Carlo simulation method for fatigue failure, by which the randomness of two material properties as well as that of the applied load can be incorporated into a stochastic model using an appropriate failure criterion to predict the statistical characteristics of fatigue life under constant and random amplitude cyclic loading conditions. In this technique, both the endurance limit Se and the fatigue strength coefficient Sf′ are treated as stochastic variables. The combined effect of the randomness of Se, Sf′, and the applied stress on the statistical characteristics of fatigue lives is predicted analytically using digital simulation of fatique tests. The life distributions and their statistical characteristics are found to be in good agreement with those obtained from analyzing the experimental results, indicating that the proposed technique and the underlying assumptions and hypotheses are adequate. The suggested method is believed to be an effective, fast, and easy-to-use design tool which is suitable for use on electronic computers. It is ideal for parametric studies compared with the costly and time-consuming laboratory fatigue tests. Minimum experimental data are needed as a basis for the analysis. New results are presented which show the effect of the randomness of the loads and material properties on the randomness of fatigue life distribution.

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