Soft Body Impact of Cantilever Beams

摘要

Damage incurred by gas turbine engine fan blades due to foreign object ingestion is of great concern to both manufacturers and the agencies that purchase such products. Of particular interest is the response of a structure impacted by a soft body, such as a bird. As a result, efforts have been made in the last several years to understand the dynamic behavior of blade-like structures under impact loading. A great deal of information is available concerning the hard body impact problem. However, the soft body impact problem has not yet been investigated as thoroughly. This study experimentally and analytically investigates the stress/time response of a cantilever beam subjected to impact loading from a soft object. Results from several different analytical models employing the Euler-Bernoulli Beam Theory are compared to experimental data, and the validity of each model is assessed. The effects of structural damping, beam dimensions and the Timoshenko Theory parameters are discussed and conclusions as to their importance are drawn. It was determined that a cantilever beam impacted by a soft body can be accurately modeled as a forced vibration problem using the Euler-Bernoulli Theory and linear modal analysis wth damping. In addition, it was shown that large structures can be linearly scaled down for impact testing without affecting the results. (Author)