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 with Stability Constraint

Abstract: The problem of minimum weight design of structures composed of finite elements each having a finite number of degrees of freedom and subject to a critical buckling load constraint is formulated as in nonlinear programming. Employing the accelerated cutting plane method of Wolfe, all constraints except the general buckling load constraint are expressed by linear inequalities. A method for the solution of this problem is developed which differs from the projected gradient method only in the way the direction of motion is selected once the nonlinear constraint is encountered. The method involves first moving in the direction of the projected gradient, and then returning to this region on the hyperplane of constant weight along the projection of the buckling-constraint gradient. The method is applied to the minimum weight design of a built-up column of varying width.

Straight-Field Permanent Magnets of Minimum Weight for TWT Focusing-Design and Graphic Aids in Design

Abstract: A convenient design formula has been derived which enables one to estimate readily the minimum amount of magnetic material which will satisfy a given set of field strength requirements on the axis of a tubular permanent magnet. Such a magnet is suitable for focusing the beam of a traveling-wave tube (twt) with coaxial rf fittings if small holes are provided in the side of the magnet to admit the coaxial lines. The calculation is further expedited by the use of design graphs, based upon the formula, from which one can read off directly the required cross section area at the middle of the magnet. From this value one may calculate the average cross section, volume, and weight of magnetic material. A correction factor has been derived which also enables one to apply the results for the simple tubular magnet directly to the case of magnets specially shaped to fit around waveguide. The validity of the formula and of the associated design graphs has been confirmed by tests upon a series of magnets. These magnets covered a considerable range of field requirements and of size, varying in weight from three to twenty pounds.

Integrated Structural and Control Optimization

Abstract: This paper focuses on the integrated structural/control optimization of a large space structure with a robot arm subject to the gravity-gradient torque through a semi-analytical approach. It is well known that the computer effort to compute numerically derivatives of the constraints with respect to design variables makes the process expensive and time-consuming. In this sense, a semi-analytical approach may represent a good alternative when optimizing systems that require sensitivity calculations with respect to design parameters. In this study, constraints from the structure and control disciplines are imposed on the optimization process with the aim of obtaining the structure’s minimum weight and the optimum control performance. In the process optimization, the sensitivity of the constraints is computed by a semi-analytical approach. This approach combines the use of analytical derivatives of the mass and stiffness matrices with the numerical solution of the eigenvalue problem to obtain the eigenvalue d...

Binary extremal self-dual codes of length 60 and related codes

Abstract: We give a classification of four-circulant singly even self-dual [60, 30, d] codes for $$d=10$$ and 12. These codes are used to construct extremal singly even self-dual [60, 30, 12] codes with weight enumerator for which no extremal singly even self-dual code was previously known to exist. From extremal singly even self-dual [60, 30, 12] codes, we also construct optimal singly even self-dual [58, 29, 10] codes with weight enumerator for which no optimal singly even self-dual code was previously known to exist. Finally, we give some restriction on the possible weight enumerators of certain singly even self-dual codes with shadow of minimum weight 1.