Optimization of Orthotropic Laminates

1967 ◽  
Vol 89 (3) ◽  
pp. 399-402 ◽  
Author(s):  
L. Fischer
Keyword(s):  
Stress Distribution ◽  
Structural Design ◽  
Single Layer ◽  
Design Criteria ◽  
Shear Stresses ◽  
Stress Strain ◽  
Mathematical Procedure ◽  
Optimum Structural Design ◽  
Interaction Equation

Stress-strain relationships for a single layer are used to obtain the stress distribution in a laminate composed of any number of orthotropic layers subjected to axial and shear stresses. The mathematical procedure is simplified for an isotropic laminate. An interaction equation is presented to predict failure of a laminate. Optimum structural design criteria are obtained by considering different combinations of layer orientations.

scholarly journals Assessing Machine Learning versus a Mathematical Model to Estimate the Transverse Shear Stress Distribution in a Rectangular Channel

Mathematics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 596
Author(s):  
Babak Lashkar-Ara ◽  
Niloofar Kalantari ◽  
Zohreh Sheikh Khozani ◽  
Amir Mosavi
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Fuzzy Inference ◽  
Rectangular Channel ◽  
Tsallis Entropy ◽  
Shear Stress Distribution ◽  
Data Series ◽  
Shear Stresses ◽  
Inference System ◽  
Aspect Ratios

One of the most important subjects of hydraulic engineering is the reliable estimation of the transverse distribution in the rectangular channel of bed and wall shear stresses. This study makes use of the Tsallis entropy, genetic programming (GP) and adaptive neuro-fuzzy inference system (ANFIS) methods to assess the shear stress distribution (SSD) in the rectangular channel. To evaluate the results of the Tsallis entropy, GP and ANFIS models, laboratory observations were used in which shear stress was measured using an optimized Preston tube. This is then used to measure the SSD in various aspect ratios in the rectangular channel. To investigate the shear stress percentage, 10 data series with a total of 112 different data for were used. The results of the sensitivity analysis show that the most influential parameter for the SSD in smooth rectangular channel is the dimensionless parameter B/H, Where the transverse coordinate is B, and the flow depth is H. With the parameters (b/B), (B/H) for the bed and (z/H), (B/H) for the wall as inputs, the modeling of the GP was better than the other one. Based on the analysis, it can be concluded that the use of GP and ANFIS algorithms is more effective in estimating shear stress in smooth rectangular channels than the Tsallis entropy-based equations.

Analysis of Lattice Single Layer Cylindrical Structures

1987 ◽  
Vol 2 (2) ◽  
pp. 87-91 ◽  
Author(s):  
Istvan HegedüS
Keyword(s):  
Stress Distribution ◽  
Matrix Method ◽  
Regular Ring ◽  
Lattice Structure ◽  
Single Layer ◽  
Cylindrical Structures ◽  
Lattice Construction

A matrix method is presented for the calculation of bar forces in a single layer lattice cylinder composed of regular ring polygons and symmetrically arranged bracing bars. Substantial differences occur between the stress distribution in the lattice structure and that of the membrane cylinder under the same load. Therefore, a membrane cylinder cannot be considered as a replacement continuum for the lattice construction. The purpose of the paper is to draw attention to the danger in the utilisation, without due caution, of this analogy.

Specification of stress limits for irradiated 316L(N)-IG steel in ITER structural design criteria

2004 ◽  
Vol 329-333 ◽  
pp. 1615-1618 ◽  
Author(s):  
G.M Kalinin ◽  
B.S Rodchenkov ◽  
V.A Pechenkin
Keyword(s):  
Structural Design ◽  
Design Criteria

Optimum Structural Design by Dynamic Programming

1976 ◽  
Vol 102 (8) ◽  
pp. 1575-1589
Author(s):  
P. Packia Raj ◽  
S. Olani Durrant
Keyword(s):  
Dynamic Programming ◽  
Structural Design ◽  
Optimum Structural Design

Optimum Structural Design of High-Speed Surface Effect Ships Built of Composite Materials

2003 ◽  
Vol 40 (01) ◽  
pp. 42-48
Author(s):  
Chang Doo Jang ◽  
Ho Kyung Kim ◽  
Ha Cheol Song
Keyword(s):  
Composite Materials ◽  
Computer Program ◽  
Structural Design ◽  
High Speed ◽  
Surface Effect ◽  
Minimum Weight ◽  
Original Design ◽  
Optimum Structural Design ◽  
Surface Effect Ship ◽  
Speed Performance

A surface effect ship is known to be comparable to a high-speed ship. For the structural design of surface effect ships, advanced design methods are needed which can reflect the various loading conditions different from those of conventional ships. Also, minimum weight design is essential because hull weight significantly affects the lift, thrust powering and high-speed performance. This paper presents the procedure of optimum structural design and a computer program to minimize the hull weight of surface effect ships built of composite materials. By using the developed computer program, the optimum structural designs for three types of surface effect ships—built of sandwich plate only, stiffened single skin plate only, and both plates—are carried out and the efficiency of each type is investigated in terms of weight. The computer program, developed herein, successfully reduced the hull weight of surface effect ships by 15–30% compared with the original design. Numerical results of optimum structural designs are presented and discussed.

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