Showing papers on "Rotary inertia published in 1977"

An Optimal Control Approach to Minimum-Weight Vibrating Beam Design

Abstract: A gradient projection algorithm is applied to a class of vibrating cantilever beam optimization problems which are formulated as optimal control problems The cross-section area is distributed along the beam for minimum total weight subject to fixed natural frequency constraints and a minimum allowed area limit Three topics receive major emphasis: the effects of shear deformation and rotary inertia, higher-mode frequency constraints, and multiple frequency constraints Computational results are presented for the cases of fixed fundamental frequency, fixed second-mode frequency, and fixed fundamental and second-mode frequencies under a variety of conditions

The Use of Inertia Relief to Estimate Impact Loads

Abstract: In order to perform an inertia relief analysis, an analyst must first select single values to represent the force time histories which are applied to the structure. These forces are then applied to a partially or totally unrestrained structure (i. e., free-free), and the resulting rigid body accelerations are calculated. From these accelerations and the mass of the structure, the inertia forces can be calculated at all points in the structure and then applied along with the original forces. Finally, the structure is restrained from rigid body motion, and a conventional static analysis is performed. If the periods of the applied loads are much greater than the periods of those modes that would be excited in the structure, this approximate technique is exact. However, should the periods of the loads be close to those of interest in the structure, then the results are not nearly as good. The dynamic responses of simple series- and parallel-connected spring-mass systems are analyzed and compared with inertia relief calculations. An important conclusion is that for masses connected in series, the error in the inertia relief results increases as one gest farther from the applied load. The final example is a space frame structure composed of welded tubular elements and representing a subcompact vehicle geometry. It is subjected to a load which is similar to that resulting from the 8 km/h (5 mph) bumper impact safety standard.

Mechanical shock arrestor

Abstract: Relative axial motion of a pair of strut members is converted into rotation of a shaft which drive a rotatably mounted inertia element. Rotation of the shaft in the opposite direction drives a second rotatably mounted inertia element. The inertia elements are interconnected by a coil spring with the result that the inertia element driven directly by the shaft drives the other inertia element. At a predetermined acceleration, the inertia element driven by the spring will lag, and this changes the spring diameter causing the spring to engage a surrounding housing causing a braking action to limit the acceleration. In a second embodiment, the axial strut load is translated through a fixed shaft into rotation of a nut which drives the inertia element. The nut also transfers the axial load through the inertia element and a single ball bearing set to the other strut member.