About project

Riga Technical University (RTU)
Institute of Materials and Structures (MKI)
Project Manager: Kaspars Kalniņš (kaspars.kalnins@rtu.lv)
Project execution start: 02.11.2018
Project duration: 24 months
Total eligible cost: 200 000 EUR

The project aims to extend Vibration correlation technique reliability for assessment imperfection sensitive composite cylindrical structures. Particularly to devote attention to robustness of the method for estimation of ultimate critical/buckling load level extracted from operationally loaded cylindrical structural natural frequency response. Up to now there is major gap in statistically reliable set of experimental data since studies like NASA/SP-8007 in 1968 where composites has been neglected. Therefore a dedicated variety of geometrical and mechanical property specimens are required to establish a guidelines to assure statistical credibility non-destructive assessment method as Vibration correlation technique. This fundamental challenge is under evaluation throughout the project by aiming for largest possible well documented series of validated set`s which can be openly accessed and to be explored as a cross checking benchmark or a reference cases for design community.

To achieve this a series of CFRP hollow circular cross section columns and cylindrical shells will be produced to vary radius/thickness ratio and radius/free height (slenderness) ratio among ply lay-up orientation. Intentionally R/t ratio are foreseen to vary between 10 to 1000 while slenderness could vary in between 50 to 1, with selected number of lay-up`s and boundary conditions this ensures a statistically meaningful test series. Each set will consist of nine specimens with constant R/t and subset of selected slenderness level specimens. A detailed design of experiments will assure a good design space distribution which are prerequisite for reliability assessment.