Minimum weight

About: Minimum weight is a research topic. Over the lifetime, 2002 publications have been published within this topic receiving 28244 citations.

Minimum weight design of laminated composite plates subject to strength constraint

Abstract: The minimum weight design of laminated composite plates subject to strength and side constraints is studied via a constrained global optimization technique. The first-ply failure load that is treated as the strength of a laminated plate is determined by using a shear deformable finite element and one of the several commonly used phenomenological failure criteria. The optimal layer group parameters (fiber angles and thicknesses of layer groups) of the laminated composite plate are determined via the proposed constrained global optimization technique for attaining the global minimum weight of the plate and satisfying the imposed constraints. A number of examples of the minimum weight design of symmetrically laminated composite plates with various aspect ratios, different number of layer groups, and different boundary conditions are given to illustrate the applications of the present constrained global optimal design method. The effects of the failure criteria on the optimal design parameters are also investigated via the examples. Finally, experimental investigation of the capability of the present method in obtaining global optima is performed. Failure tests of a number of graphite/epoxy laminates designed by different methods are performed, and the superiority of the present method over the other methods is demonstrated via the test results.

A high threshold code for modular hardware with asymmetric noise

Abstract: We consider an approach to fault tolerant quantum computing based on a simple error detecting code operating as the substrate for a conventional surface code. We develop a customised decoder to process the information about the likely location of errors, obtained from the error detect stage, with an advanced variant of the minimum weight perfect matching algorithm. A threshold gate-level error rate of 1.42% is found for the concatenated code given highly asymmetric noise. This is superior to the standard surface code and remains so as we introduce a significant component of depolarising noise; specifically, until the latter is 70% the strength of the former. Moreover, given the asymmetric noise case, the threshold rises to 6.24% if we additionally assume that local operations have 20 times higher fidelity than long range gates. Thus for systems that are both modular and prone to asymmetric noise our code structure can be very advantageous.

Cover for manhole structures

Abstract: A cover for manhole structures embodying a metal portion constructed of high strength material and assembled to provide maximum strength with a minimum of weight. A concrete portion is carried by the metal portion with the weight of the concrete portion being so proportioned relative to the weight of the metal portion that the combined weight thereof provides a manhole cover of a predetermined minimum weight.

Optimal Plastic Design of Plates, Shells and Shellgrids

Abstract: In this paper, recent work on the optimal plastic design of plates, shells and shellgrids is reviewed critically and certain important conclusions are arrived at. Of particular significance is the finding that the minimum weight design of solid plates and shells with a maximum thickness constraint contains a theoretically infinite number of rib-like formations. At relatively low load intensities, the layout of such ribs is furnished by the classical optimal grillage theory but at higher load levels a more advanced formulation is necessary. The latter has also been extended from optimal plastic design to optimal elastic design with stress, compliance and deflection constraints and this extended theory has been applied to plates. Moreover, it is shown that ribs in the solution can be suppressed by introducing additional geometrical constraints (termed “Niordson-constraints”) or segmentation.