Theory Extension and Numerical Experiments to Determine the Probability of Exceedance of Given Load Levels in Specified Times.

摘要

Extensions to the theory of the 'first encounter' problem are developed. Numerical experiments with actual time histories were conducted to establish the probability density distribution functions for the intervals between like crossings. Time histories considered include a random function, verticle acceleration records due to gust encounter, and vertical gust velocities of continuous atmospheric turbulence. It appears that the density distribution function for practical cases can be represented well by two exponential terms (a single term applies to a time sequence of independent events). The associated curves giving the probability of encountering a given level of the phenomenon under consideration in a specified time are developed. Examples are given to show application in the gust loads encounter problem.