Mechanics of Screw Joints Solved as Beams Placed in a Tangential Elastic Foundation

• Main Authors: Karel Frydrýšek, Šárka Michenková, Leopold Pleva, Jan Koutecký, Jiří Fries, Kateřina Peterek Dědková, Roman Madeja, Antonín Trefil, Pavel Krpec, Tomáš Halo, Leopold Hrabovský, Lubor Bialy, Roland Jančo, Jiří Pokorný
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Applied Sciences
• Subjects: screw joints; tensile stress; pull-out test; analytical and experimental solution; wood; tangential elastic foundation
• Online Access: https://www.mdpi.com/2076-3417/11/12/5616

This article deals with a new original analytical solution of deformation, force and stress states in wood screw joints up to the limit values of pulling out/breaking the screw. The screws are under tension. The wood-to-screw interaction is effectively simplified by introducing several physical model variants using a tangential elastic non-linear foundation. The experimental verification of the proposed models using pull-out tests (i.e., pulling out screws from dry spruce wood in laboratory conditions) confirms the correctness of the proposed models of the elastic linear/non-linear foundation. The validity of the model is also analytically and experimentally verified in the biomechanical model of pulling out screws from the femur of a bovine/human cadaver, which confirms and expands the validity of newly designed screw joint models outside the timber structure area.