Adaptive structures in civil engineering

Bridges and load bearing frame constructions consists trusses connected by rigid joints. In this project we develop a smart joint which can switch between flexible and rigid by means of thermal actuation. The joint consists of a shape memory polymer (SMP) core and a thin Kevlar-SMP shell. The SMP core material changes from being stiff to rubbery when heated to around 65 C. In this state the joint is flexible and the construction is able to change shape (e.g. by one or more pistons). Cooling down below 50 C then fixates the new shape. The SMP impregnated Kevlar shell is added to limit the total deformation of the joints when in activated state.

Next to the shape change mechanism described above, our new variable stiffness structural joints are also quite effective in damping vibrations in a loaded truss structure. In order to test this we built a three-floor demonstrator structure with 12 active variable stiffness joints. The construction was then submitted to vibrations at different frequencies as well as to a series of simulated earthquake loadings. As can be seen in the video below, the vibration suppression of our new adaptive joints is impressive.

Three-floor test setup for experimental verification
Detail of the smart joint structure in test setup
Simulation results of 3-floor frame
Damping predictions with elastic and viscoelastic material models
Response of 3-floor test setup due on shaking table. Actuation of the joints results in strong damping of the vibrations

More information

  • Qinyu Wang, Gennaro Senatore, Kaspar Jansen, Arjan Habraken, Patrick Teuffel, Design and characterisation of variable stiffness structural joints, Materials and Design 187: 108353 (2020)
  • Qinyu Wang, Gennaro Senatore, Kaspar Jansen, Arjan Habraken, Patrick Teuffel, Experimental testing of vibration control through adaptive joints, Proceedings of the IASS symposium 2020, 24-28 August 2020, Guilford, UK
  • Qinyu Wang, Gennaro Senatore, Kaspar Jansen, Arjan Habraken, Patrick Teuffel, Vibration suppression using variable stiffness structural joints
  • Q. Wang, A. Habraken, P. Teuffel, G, Senatore and KM.B. Jansen, Characterization of variable stiffness joints for adaptive structures, Structural Mechanics and Engineering Conference, 2-4 sept 2019, Cape Town, South Africa

Research team

  • Qinyu (Jady) Wang, 
    PhD student Eindhoven University
  • Prof. Patrick Teuffel,
    Eindhoven University
  • Dr. Arjan Habraken,
    Eindhoven University
  • Dr. Gennaro Senatore,
    Swiss Federal Institute of Technology (EPFL)
  • Prof. K.M.B. Jansen,
    Delft University of Technology