\IMinimum Design Loads for Buildings and Other Structures\N gives requirements for dead, live, soil, wind, snow, rain, and earthquake loads, as well as their combinations. The requirements described in this standard—which is a complete revision of ANSI A58.1-1982—are suitable for inclusion in building codes and other design documents. The Standard also includes a Commentary, which describes the basis of the requirements.

Minimum Design Loads for Buildings and Other Structures

Performance of an active control system with piezoelectric actuators

This paper describes a novel implementation of the Simulated Annealing algorithm designed to explore the trade-off between multiple objectives in optimization problems. During search, the algorithm maintains and updates an archive of non-dominated solutions between each of the competing objectives. At the end of search, the final archive corresponds to a number of optimal solutions from which the designer may choose a particular configuration. A new acceptance probability formulation based on an annealing schedule with multiple temperatures (one for each objective) is proposed along with a novel restart strategy. The performance of the algorithm is demonstrated on three examples. It is concluded that the proposed algorithm offers an effective and easily implemented method for exploring the trade-off in multiobjective optimization problems.

A simulated annealing algorithm for multiobjective optimization

Active vibration control of flexible beams using shape memory actuators

Control system design for hypersonic vehicles will be complicated by coupling effects between aerodynamics, propulsion, and structure. Using H1 and π-synthesis techniques, these features can be modeled as uncertainties and incorporated into the design procedure of a e ight control system. However, modern control theory techniques generallyleadtohigh-ordercontrollers.Thetimedelays,whicharecreatedwhenthesecontrollersareimplemented, may not be acceptable. A technique to constrain controller dimension a priori in the design process is used to design e xed-order π controllers that are robust to mixed real/complex uncertainties. Typical hypersonic effects such as propulsion system perturbations and aeroelastic fuselage bending are modeled as uncertainties in a robust control design framework. Three different e xed-order controllers are synthesized for a hypersonic vehicle model accelerating through Mach 8. A comparison with full-order and reduced-order designs is conducted and the results illustrate that the e xed-order controllers exhibit robustness properties similar to full-order designs while considerably reducing controller complexity.

Uncertainty Modeling and Fixed-Order Controller Design for a Hypersonic Vehicle Model

Part I: structures modelled as a single degree-of-freedom system undamped single degree-of-freedom system damped single degree-of-freedom system response of one-degree-of-freedom system to haarmonic loading response to general dynamic loading Fourier analysis and response in the frequency domain generalized co-ordinates and Rayleigh's method nonlinear structural response response spectra. Part II: structures modelled as shear buildings the multistory shear building free vibration of a shear building forced motion of shear buildings damped motion of shear buildings reduction of dynamic matrices. Part III: framed structures modeled as discrete multidegree-of-freedom systems dynamic analysis of beams dynamic analysis of plane frames dynamic anaylsis of grids three-dimensional frames dynamic analysis of trusses time history response of multidegree-of-freedom systems. Part IV: structures modelled with distributed properties dynamic analysis of systems with distributed properties discretization of continuous systems. Part V: introduction to finite element method dynamic analysis of plates dynamic analysis of shells dynamic analysis of three-dimensional solid structures. Part VI: random vibration. Part VII: earthquake engineering equivolent staic lateral force method - uniform Building Code 1994 dynamic method - uniform Building Code - 1994.

F. H. Berkshire

Papers

Structural dynamics—theory and computation, by Mario Paz. Pp 446. £22·45. 1980. ISBN 0 442 23019 2 (Van Nostrand Reinhold)