Research in structural mechanics deals with the studies of how complex structures are affected by different loads. Structures studied vary in scale from the smallest wooden cells up to bridges and buildings, and how the characteristics of these scales interact.
Our research includes the use and the development of computer based methods such as the finite element method, FEM. A computer model of a structure is built up by describing the material properties, geometry and location of the individual parts, as well as the forces acting on the structure. From this model one can simulate how the structure deforms, if it will break, how it vibrates and how it interacts with the surroundings.
The theoretical models are validated by testing in the laboratory or in-situ. The department has, among other things, mechanical testing equipment, including a larger plant with a total of 60 load rigs for duration-of-load testing of structural elements in outdoor sheltered climate (information sheet).
More information on current research and contacts is described under the following headings:
Typical research questions relate to the load bearing capacity of structural elements and joints, dynamic behaviour such as vibration and resonance phenomena of structures and blast loading.
This topic relates to the studies of how a structure's vibrations interact with surrounding fluids, for example, in water pipes, in air that vibrates with a wall, causing noise transmission or the wind flowing around an aircraft wing.
In order to predict how a structure will behave, one must know the mechanical properties of the material as described in terms of stiffness, strength, fracture properties, creep, temperature or humidity related deformations, etc. Materials studied include concrete, glass and elastomers like rubber. Wood-based materials are treated under the next heading.
We have a long tradition of studying wood and wood-based materials. Typical topics include prediction of load bearing capacity, dimensional stability during drying, properties of wood-based paper-, fiber- and composite materials, as well as properties of glued joints and engineered wood products (glued laminated timber, cross laminated timber).
The department has access to advanced measuring equipment such as a servo hydraulic tensile test machine, accelerometers, load cells, shakers to provide dynamic loads and the possibility of performing non-contact measurement (digital image correlation, DIC). Measurements can be used to evaluate the characteristics of different materials or to validate calculations on real structures.
FE calculations of structures create large systems of equations solved with computers. It has created a need to develop computational methods and software, as well as methods of using large clusters of computers. Structural mechanics is therefore closely linked to the supercomputer center at LU, Lunarc.
The work by the research group at the Division of Structural Mechanics on Vibrations in the Built Environment is primarily driven by the need to understand physical phenomena and the desire to develop engineering solutions to vibration problems affecting stakeholders in the built environment. The research problems we are focusing on require a synergy of physical experimental testing and/or computational simulations based on applied mechanics and on applied mathematics.