THEORETICAL AND COMPUTATIONAL METHODS FOR COMPOSITE STRUCTURES -- A SURVEY OF COMPUTER PROGRAMS

In Rucho v. Common Cause, the Supreme Court held that challenges to partisan gerrymanders presented a nonjusticiable political question. This decision threatened to discard decades of work by political scientists and other experts, who had developed a myriad of techniques designed to help the courts objectively and unambiguously identify excessively partisan district maps. Simulated redistricting promised to be one of the most effective of these techniques. Simulated redistricting algorithms are computer programs capable of generating thousands of election-district maps, each of which conforms to a set of permissible criteria determined by the relevant state legislature. By measuring the partisan lean of both the automatically generated maps and the map put forth by the state legislature, a court could determine how much of this partisan bias was attributable to the deliberate actions of the legislature, rather than the natural distribution of the state’s population.Rucho ended partisan gerrymandering challenges brought under the U.S. Constitution—but it need not close the book on simulated redistricting. Although originally developed to combat partisan gerrymanders, simulated redistricting algorithms can be repurposed to help courts identify intentional racial gerrymanders. Instead of measuring the partisan bias of automatically generated maps, these programs can gauge improper racial considerations evident in the legislature’s plan and demonstrate the discriminatory intent that produced such an outcome. As long as the redistricting process remains in the hands of state legislatures, there is a threat that constitutionally impermissible considerations will be employed when drawing district plans. Simulated redistricting provides a powerful tool with which courts can detect a hidden unconstitutional motive in the redistricting process.

Download Full-text

Delamination Under Fatigue Loads in Composite Laminates: A Review on the Observed Phenomenology and Computational Methods

Applied Mechanics Reviews ◽

10.1115/1.4027647 ◽

2014 ◽

Vol 66 (6) ◽

Cited By ~ 75

Author(s):

Brian L. V. Bak ◽

Carlos Sarrado ◽

Albert Turon ◽

Josep Costa

Keyword(s):

Design Process ◽

Computational Methods ◽

Structural Design ◽

Composite Laminates ◽

Composite Structures ◽

State Of The Art ◽

Computational Simulation ◽

Simulation Methods ◽

Short Term ◽

Current State

Advanced design methodologies enable lighter and more reliable composite structures or components. However, efforts to include fatigue delamination in the simulation of composites have not yet been consolidated. Besides that, there is a lack of a proper categorization of the published methods in terms of their predictive capabilities and the principles they are based on. This paper reviews the available experimental observations, the phenomenological models, and the computational simulation methods for the three phases of delamination (initiation, onset, and propagation). It compiles a synthesis of the current state-of-the-art while identifying the unsolved problems and the areas where research is missing. It is concluded that there is a lack of knowledge, or there are unsolved problems, in all categories in the field, but particularly in the category of computational methods, which in turn prevents its inclusion in the structural design process. Suggested areas where short-term and midterm research should be focused to overcome the current situation are identified.

Download Full-text

Seismological Algorithms, Computational Methods and Computer Programs

Physics of The Earth and Planetary Interiors ◽

10.1016/0031-9201(89)90062-9 ◽

1989 ◽

Vol 58 (2-3) ◽

pp. 268-269

Author(s):

R.C. Lilwall

Keyword(s):

Computational Methods ◽

Computer Programs

Download Full-text

In Situ microscopy of the anodic etching of silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100137537 ◽

1995 ◽

Vol 53 ◽

pp. 232-233

Author(s):

Frances M. Ross ◽

Peter C. Searson

Keyword(s):

Composite Structures ◽

High Surface ◽

High Surface Area ◽

Chemical Properties ◽

Selective Etching ◽

Silicon On Insulator ◽

Second Phase ◽

Porous Layers ◽

New Class ◽

Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

Download Full-text