Background of Design Selection of Engineering Materials for Construction of Precision Space Structures

2021 ◽  
Vol 55 (7) ◽  
pp. 704-708
Author(s):  
A. A. Moisheev
Keyword(s):  
Space Structures ◽  
Engineering Materials ◽  
Design Selection ◽  
Selection Of

scholarly journals Asymptotic Expansions and Strategies in the Online Increasing Subsequence Problem

2021 ◽  
Vol 174 (1) ◽  
Author(s):  
Amirlan Seksenbayev
Keyword(s):  
Dynamic Programming ◽  
Asymptotic Expansions ◽  
Dual Problem ◽  
Infinite Length ◽  
Expected Time ◽  
Selection Strategies ◽  
Dynamic Programming Equation ◽  
Optimal Values ◽  
Design Selection ◽  
Selection Of

AbstractWe study two closely related problems in the online selection of increasing subsequence. In the first problem, introduced by Samuels and Steele (Ann. Probab. 9(6):937–947, 1981), the objective is to maximise the length of a subsequence selected by a nonanticipating strategy from a random sample of given size $n$ n . In the dual problem, recently studied by Arlotto et al. (Random Struct. Algorithms 49:235–252, 2016), the objective is to minimise the expected time needed to choose an increasing subsequence of given length $k$ k from a sequence of infinite length. Developing a method based on the monotonicity of the dynamic programming equation, we derive the two-term asymptotic expansions for the optimal values, with $O(1)$ O ( 1 ) remainder in the first problem and $O(k)$ O ( k ) in the second. Settling a conjecture in Arlotto et al. (Random Struct. Algorithms 52:41–53, 2018), we also design selection strategies to achieve optimality within these bounds, that are, in a sense, best possible.

scholarly journals Mooring Design Selection of Aquaculture Cage for Indonesian Ocean

2018 ◽  
Vol 135 ◽  
pp. 012022
Author(s):  
Y Mulyadi ◽  
N Syahroni ◽  
K Sambodho ◽  
M Zikra ◽  
Wahyudi ◽  
...  
Keyword(s):  
Design Selection ◽  
Selection Of

Tensile Testing at Low Temperatures

2004 ◽  
pp. 239-249
Keyword(s):  
Low Temperatures ◽  
Tensile Testing ◽  
Fiber Reinforced Polymer ◽  
Compression Tests ◽  
Test Procedures ◽  
Safety Issues ◽  
Reinforced Polymer ◽  
Engineering Materials ◽  
Temperature Test ◽  
Selection Of

Abstract This chapter details low-temperature test procedures and equipment. It discusses the role temperature plays in the properties of typical engineering materials. The effect that lowering the temperature of a solid has on the mechanical properties of a material is summarized for three principal groups of engineering materials: metals, ceramics, and polymers (including fiber-reinforced polymer). The chapter describes the factors that influence the selection of tensile testing, along with a comparison of tensile and compression tests. It covers the parameters and standards related to tensile testing. The chapter discusses the factors involved in controlling test temperature. Finally, the chapter discusses the safety issues concerning the use of cooled methanol, liquid-nitrogen, and liquid helium.

Combined Mechanical Engineering Materials Lecture and Mechanics of Materials Laboratory: Cross-Disciplinary Teaching

2005 ◽  
Author(s):  
Michael D. Nowak
Keyword(s):  
Biomedical Engineering ◽  
Mechanical Engineering ◽  
Engineering Students ◽  
Soft Tissues ◽  
Materials Science ◽  
Tensile Shear ◽  
Engineering Programs ◽  
Mechanics Of Materials ◽  
Engineering Materials ◽  
Selection Of

We have developed a course combining a Mechanical Engineering Materials Laboratory with a Materials Science lecture for a small combined population of undergraduate Mechanical and Biomedical Engineering students. By judicious selection of topic order, we have been able to utilize one lecture and one laboratory for both Mechanical and Biomedical Engineering students (with limited splitting of groups). The primary reasons for combining the Mechanical and Biomedical students are to reduce faculty load and required resources in a small university. For schools with medium or small Mechanical and Biomedical Engineering programs, class sizes could be improved if they could include other populations. The heterogeneous populations also aid in teaching students that the same engineering techniques are useful in more than a single engineering realm. The laboratory sections begin with the issues common to designing and evaluating mechanical testing, followed by tensile, shear, and torsion evaluation of metals. To introduce composite materials, wood and cement are evaluated. While the Mechanical Engineering students are evaluating impact and strain gauges, the Biomedical Engineering students are performing tensile studies of soft tissues, and compression of long bones. The basic materials lectures (beginning at the atomic level) are in common with both Mechanical and Biomedical student populations, until specific topics such as human body materials are discussed. Three quarters of the term is thus taught on a joint basis, and three or four lectures are split. Basic metal, plastic and wood behavior is common to both groups.

Analysis of Brief Tension Loss in TLP Tethers

1988 ◽  
Vol 110 (1) ◽  
pp. 43-47 ◽  
Author(s):  
J. N. Brekke ◽  
T. N. Gardner
Keyword(s):  
Time Domain ◽  
Large Diameter ◽  
Nonlinear Effects ◽  
Response Analysis ◽  
Bending Stress ◽  
Large Wave ◽  
Wave Trough ◽  
Design Selection ◽  
The Time Domain ◽  
Selection Of

The avoidance of “slack” tethers is one of the factors which may establish the required tether pretension in a tension leg platform (TLP) design. Selection of an appropriate safety factor on loss of tension depends on how severe the consequences may be. It is sometimes argued that if tethers go slack, the result may be excessive platform pitch or roll motions, tether buckling, or “snap” or “snatch” loading of the tether. The results reported here show that a four-legged TLP would not be susceptible to larger angular motions until two adjacent legs lose tension simultaneously. Even then, this analysis shows that a brief period of tether tension loss (during the passage of a large wave trough) does not lead to excessive platform motion. Similarly, momentary tension loss does not cause large bending stress in the tether or significant tension amplification as the tether undergoes retensioning. This paper presents TLP platform and tether response analysis results for a representative deepwater Gulf of Mexico TLP with large-diameter, self-buoyant tethers. The time-domain, dynamic computer analysis included nonlinear effects and platform/tether coupling.

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