A Similarity Transformation for Numerical Integration of Piecewise-Linear Second-Order Differential Equations Without Damping

Article Abstract:

The rigid and flexible dynamic behavior of many systems in aerospace structures can be modeled by a set of coupled nonlinear second-order differential equations. In these systems, the mass matrix function of the system, which contains the masses of the different modules in the structure, its moment of inertia tensors, and its bending moment coefficients (finite number of modes), exhibits eigenvalue dispersion between four and nine orders of magnitude. In addition, due to small gravity gradient and aerodynamic forces and moments, these systems are acted on by small or negligible damping forces and moments. The two characteristics alluded to above imply that the differential equations representing these systems have poor numerical stability properties. This study is concerned with the development of a similarity transformation on the variables of integration which results in an equivalent system with high damping and consequently better numerical stability than the original one. (Reprinted by Permission of Publisher.)

Algorithms, Numerical analysis, Algorithm, Aerospace engineering, Stability, Integral Equations, Transforms, Matrix Computations, Ordinary Differential Equations

---

Simulation Based Design of Hydraulic Servo-Controlled Apparatus for Damping Measurement

Article Abstract:

Measurement of a material's damping property requires a complex apparatus. This apparatus utilizes a thin-walled cylindrical chamber which could buckle under system pressure that is not carefully regulated. Furthermore, factors such as gland leakage and specimen deflection are difficult to define. In order to assess these factors, simulation was employed as part of the apparatus design process. A run of the analog model established the feasibility of building the apparatus and provided operating and performance information. The apparatus was built; as anticipated, performance was slightly inferior to the idealized model. However, the apparatus proved usable with care taken in its operation. Graphs illustrating various simulated and actual performance indices, as well as tables of symbols and design data, are included.

Computer aided design, Servomechanisms, Mechanical engineering, Computer-Aided Design, Analog Systems

---

Flight simulation for museums (a numerical solution of the equations of flight)

Article Abstract:

A generalized microcomputer based flight simulator has been developed, one part of this simulator is a numerical solution of the equations of flight. For accurate solution, a simple numerical scheme would demand a very small timestep: A modified scheme is therefore developed which allows a much larger timestep to be used by introducing certain scaling factors. These factors are themselves functions of the timestep and of the characteristic response time of the equations being solved. The modified numerical scheme is shown to be adequate when applied to simultaneous solutions of all the components of an aircraft motion. Within limits, the simulation is independent of the aircraft being simulated. Relevant performance and control parameters are entered before the commencement of solution.

Mathematical models, Museums, Microcomputer, Flight Simulator, Scientific Research, technical

Similar abstracts:

• Abstracts: Replanning timing in hierarchical production planning. Comparing integration strategies in production ordering systems
• Abstracts: Automatic VLSI Layout Simulation. Simulation of a Three-Dimensional Semiconductor Device
• Abstracts: Real-time simulation of air traffic control radar terminal with trainer interface. Cubic Corporation Awarded Two Contracts
• Abstracts: An expert system framework based on a simulation generator. An Efficient Generator of Uniformly Distributed Random Variates between Zero and One

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.