Nonlinear Mechanics of Prestressed Stayed Columns

Advancements in the fields of digital design and fabrication have facilitated the development of complex architectural concepts that are driving equally novel structural solutions for these to be realised. This scenario is exemplified in the design and fabrication of doubly-curved plates which are currently limited by the European design code for steel structures, which does not provide guidance for the structural design of curved plates. While recent studies considering the behaviour of cylindrically-curved plates (i.e. plates having a constant radius of curvature in one plane) under various load conditions have been published, there is very limited research considering the behaviour of doubly-curved plates under in-plane loading and this is the primary aim of this research project. The currently described problem will be tackled initially by deriving and investigating nonlinear analytical models of hyperbolic paraboloidal shaped plates, the objective being to provide an understanding of the mechanical behaviour of the doubly-curved plate to the loading and boundary conditions considered. These analytical models will be verified and validated against numerical models formulated using the Finite Element Method. This well-established methodology will provide confidence in the results of a parametric study, which will test the influence of additional parameters, such as the effects of initial geometric imperfections, plate thickness, plate aspect ratio and residual stresses from manufacturing, on the load-carrying capacity of the plates.

The ultimate aim of this research project is to formulate design recommendations for doubly-curved plates under various loading conditions, in a manner that such recommendations can be implemented in future versions of the design codes for use by practising engineers.

Research Questions
What is the mechanical behaviour of doubly curved plates under various in plane loading conditions?
How can engineers design for the failure modes to ensure safe and efficient performance of such structural forms?

Approach
Analytical models will be derived, using established energy principles that consider the hyperbolic paraboloid shaped plates under a variety of in plane loading and boundary conditions.
The analytical models will be additionally verified and validated against numerical models formulated using the Finite Element Method.
A parametric study that tests the influence of additional parameters, such as the effects of initial geometric imperfections, plate thickness, plate aspect ratio and residual stresses from manufacturing, on the load-carrying capacity of the plates.
Identify correlations between the parameters explored and derive relationships that allow such considerations to be implemented into the design codes for use in industrial practice

Complex geometries are becoming more prevalent in engineering with advancements in both design and fabrication technologies. The safety and reliability of these structures require fundamental mechanical principles to understand the behaviour of such geometries under loads encountered in practice, which this research project aims to address.

EPSRC Research areas: Engineering Design, Non-linear systems, Structural Engineering
EPSRC Priority areas: Engineering sciences, Lightweight systems, Structural integrity and materials behaviour