A Dynamic Ptotoelastic Study of Flexural Wave Generation in a Model of Percussive Drilling

• The development of the percussive drilling machine has led to a situation where the drill steel itself has become a major noise source. A qualitative theory for the generation of this noise is presented. In this theory the longitudinal drilling pulse is partially converted to flexural motion by non-symmetric boundary conditions. The technique of stress optics combined with high speed photography is used in conjunction with Araldite models of the drill steel to verify the above conjectures. The models are then used to demonstrate the importance of the clamping conditions in preventing the growth of noise producing motions of the drill steel. It is also shown that the Araldite models give a reasonable representation of the stress wave pattern in a true drill steel, at least for the time period associated with the first few passes of the primary stress wave pattern and its reflexions.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)

Keyword

Strömningslära

Fluid Mechanics

Publication and Content Type

ref (subject category)

art (subject category)