John Vantomme

Evaluation of structural joints in composites with modal parameters

Abstract The paper examines if modal parameters can be used in non-destructive test (NDT) methods for the control of the structural integrity of joints in large glass fiber reinforced polyester structures. Therefore, an attempt is made to look for a correlation between modal parameters and the accumulated damage of the joints of a stiffened plate structure that is subjected to several underwater explosions with successively higher shock loadings, until debonding of rib and panel is obtained. Attention is paid to the method used for the determination of the modal parameters. The evolution of the modal parameters in relation to the accumulated damage is discussed, after which it is concluded that modal frequency measurements are more appropriate as parameters in NDT of large structures than modal damping measurements.

Modelling of an IPC-concrete modular pedestrian bridge

This paper shows the usefulness of FEM in the design process of a modular bridge composed of a concrete deck and three truss girders made of inorganic phosphate cement (IPC) sandwich panels. The analytical calculation of the truss, which is based on simplified hypotheses concerning the structural behaviour and the constitutive behaviour of the IPC, is validated by FEM. The design of the connections is done by FEM in order to control the distribution of the stresses in the panels and in the connection elements. The result of the design is satisfactory and is the basis for the future realisation of a prototype bridge.

Performance of Sacrificial Cladding Structure Made of Empty Recyclable Metal Beverage Cans under Large-Scale Air Blast Load

This paper demonstrates the use of recyclable waste products such as typical empty metal beverage cans available in the market for the protection of civil engineering structures from an explosive load. The sacrificial cladding structure was made of empty recyclable beverage cans and sandwich composite skin plates. To measure the protection efficiency of these structures large-scale air blast experiments have been conducted. To create a perfect plane shock wave the concept of shock tube was used using concrete sewage pipes. The experimental and numerical crushing performance of the empty beverage cans is studied in detail. Finally, this study concludes that the waste empty metal cans can be considered as a potential member to protect civil engineering structures from the air blast load.

Impact Study of Textile Reinforced Cementitious Materials: Test Method and Preliminary Results

In building engineering, impact loading and other accidental loads are mostly taken into consideration by measures on the structural level rather than on the material level, the latter one is even seldom explored. Textile reinforced Cements (TRCs) is a composite material group which is still in full development. Its potential to dissipate a significant amount of energy under low velocity impact loading was already indicated in a preliminary study. In the present study, the low velocity impact behaviour of TRC laminates is investigated more closely and this by means of an instrumented drop weight test. This study has shown the ability of the used test method to identify damage mechanisms underlying the energy absorption under low velocity impact loading in TRC composite laminates.

Computer simulation and experiments to evaluate digital image correlation methods

Digital image correlation is an optical-numerical full field displacement measurement technique, which is more and more widely used in experimental mechanics[l-3]. The technique is based on a numerical comparison of digitized images taken at different stages of deformation of an object. In principle, any imaging technique can be used, provided that the deformed image can be predicted starting from the undeformed image and the displacement field. The digital image correlation technique then consists of numerically searching the space of all possible displacement fields, to find the displacement field which gives the best correlation of the predicted image with the actual image of the deformed state.