Modélisation thermomécanique de maçonneries : endommagement d’un piédroit de cokerie sous l’effet de la poussée du charbon

摘要

To face coke and steel market requirements, the coking process has to be more flexible. Changing process parameters such as coking temperature, blend composition and cooking time can damaged coke oven battery heating wall. Indeed, the coking process generates a swelling pressure on wall which depends on a lot of parameters. To study this point, a European project named « Swelling PRessure In a coke oven, Transmission on oven walls and COnsequences on wall » has been set up. This work is a part of it and aims to determine the admissible pushing pressure for the coke oven heating walls to prevent crack formation. To model large masonries composed of numerous bricks, a mesoscopic point of view is more appropriate. Bricks and mortar are replaced by a Homogeneous Equivalent Material (HEM) whose behaviour depends on the joint state. In order to represent joint opening mechanism, a Mohr-Coulomb criterion in stress is used. This criterion compares the level of stress to the ultimate tensile or shear stress at mesoscopic scale. Ultimate stresses are obtained thanks to an experimental campaign using a new protocol developed at PRISME Laboratory. The brick-Mortar behaviour is experimentally characterised at high temperature (20°C to 1000°C). To validate the tensile test developed, a second experimental campaign using “wedge splitting tests” has been done at Leoben University. Results are similar and confirm the importance of the brick surface state. Depending on the initial damage of the structures, mesoscopic stresses are obtained by localization tensor or by sub-Modelling. The sub-Modelling step aims to simulate a local part of the masonry at the mesoscopic scale. This step aims to simulate with a mesoscopic point of view a local part of the global model. This numerical tool has been validated thanks to a literature test. Finally, the numerical tool has been used to characterise the influence of some parameters (thermal, force due to the cross tie rod,..). Next, the simulation of the whole coke oven heating wall has been performed (undamaged or initially damaged masonry). These FE simulations show the influence of initial damage on the final masonry damage. Finally, a two flues model with beams is proposed to take into account compression due to cross tie rod and to limit computational cost. It permits to obtain better results than the existing two flues model used at CPM with a lower cost compared to the whole coke oven heating wall model.