Galerkin's approximation to minimum weight structures with dynamic constraints

This paper presents a study of multi-objective optimization of elastic beams with minimum weight and radiated sound power. The goal of this research is to discover the potentials to design multi-objective optimal elastic structures for better acoustic performance. We discuss various structural-acoustic properties of the Pareto solutions of the multi-objective optimization problem (MOP). We have found that geometrical and dynamic constraints can substantially reduce the volume fraction of feasible solutions in the design space, which can make it difficult to search for the optimal solutions. Several case studies with different boundary conditions are studied to demonstrate the multi-objective optimal designs of the structure.

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On the convergence quality of minimum-weight design of large space frames under multiple dynamic constraints

Structural Optimization ◽

10.1007/bf01742738 ◽

1992 ◽

Vol 4 (3-4) ◽

pp. 156-164 ◽

Cited By ~ 6

Author(s):

O. G. McGee ◽

K. F. Phan

Keyword(s):

Minimum Weight ◽

Minimum Weight Design ◽

Large Space ◽

Dynamic Constraints ◽

Space Frames ◽

Weight Design

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Form Follows Availability – Designing Structures Through Reuse

Journal of the International Association for Shell and Spatial Structures ◽

10.20898/j.iass.2019.202.033 ◽

2019 ◽

Vol 60 (4) ◽

pp. 257-265 ◽

Cited By ~ 1

Author(s):

Jan Brütting ◽

Gennaro Senatore ◽

Corentin Fivet

Keyword(s):

Structural Design ◽

Minimum Weight ◽

Major Influence ◽

Building Structures ◽

Structural Elements ◽

New Paradigm ◽

New Material ◽

Section Type ◽

Minimum Weight Structures ◽

Structure Layout

This work proposes a new direction in structural design: the synthesis of structures through the reuse of elements. Reusing structural elements reduces the environmental impacts of building structures because it avoids sourcing new material, it reduces waste and it requires little energy. Designing structures from reused elements is unlike conventional structural design because stock element availability is a design input. In other words, structures must be designed subject to availability of given element characteristics such as length and cross-section type, which have a major influence on the optimal structure layout and form. In this new paradigm structural form follows availability. In this work new computational methods for the synthesis of reticular structures through reuse are formulated to address two scenarios: a) reuse of reclaimed elements from a given stock, and b) design of an element stock which is used as a kit of parts to build diverse structures. Case studies are presented to demonstrate the potential of the proposed methods. It is shown that structures produced by these methods have a significantly lower environmental impact than minimum weight structures made of new elements.

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Further Studies on the Mechanisms for the Antithrombotic Effects of Sulfated Polysaccharides in Rabbits

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647027 ◽

1988 ◽

Vol 60 (02) ◽

pp. 188-192 ◽

Cited By ~ 15

Author(s):

F A Ofosu ◽

F Fernandez ◽

N Anvari ◽

C Caranobe ◽

F Dol ◽

...

Keyword(s):

Antithrombin Iii ◽

Ex Vivo ◽

Thrombus Formation ◽

Minimum Weight ◽

Sulfated Polysaccharides ◽

Pentosan Polysulfate ◽

Heparin Cofactor Ii ◽

Thrombin Inhibition ◽

The Relationship ◽

Prothrombin Activation

SummaryA recent study (Fernandez et al., Thromb. Haemostas. 1987; 57: 286-93) demonstrated that when rabbits were injected with the minimum weight of a variety of glycosaminoglycans required to inhibit tissue factor-induced thrombus formation by —80%, exogenous thrombin was inactivated —twice as fast in the post-treatment plasmas as the pre-treatment plasmas. In this study, we investigated the relationship between inhibition of thrombus formation and the extent of thrombin inhibition ex vivo. We also investigated the relationship between inhibition of thrombus formation and inhibition of prothrombin activation ex vivo. Four sulfated polysaccharides (SPS) which influence coagulation in a variety of ways were used in this study. Unfractionated heparin and the fraction of heparin with high affinity to antithrombin III potentiate the antiproteinase activity of antithrombin III. Pentosan polysulfate potentiates the activity of heparin cofactor II. At less than 10 pg/ml of plasma, all three SPS also inhibit intrinsic prothrombin activation. The fourth agent, dermatan sulfate, potentiates the activity of heparin cofactor II but fails to inhibit intrinsic prothrombin activation even at concentrations which exceed 60 pg/ml of plasma. Inhibition of thrombus formation by each sulfated polysaccharides was linearly related to the extent of thrombin inhibition achieved ex vivo. These observations confirm the utility of catalysis of thrombin inhibition as an index for assessing antithrombotic potential of glycosaminoglycans and other sulfated polysaccharides in rabbits. With the exception of pentosan polysulfate, there was no clear relationship between inhibition of thrombus formation and inhibition of prothrombin activation ex vivo.

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