TY - JOUR
TI - Thermal effect on the thermomechanical behavior of contacts in a Traveling Wave Tube
AU - Chbiki Mounir
AU - Botelho Tony Da Silva
AU - Bauzin Jean-Gabriel
AU - Laraqi Najib
AU - Jarno Jean-Francois
JN - Thermal Science
PY - 2016
VL - 20
IS - 6
SP - 1983
EP - 1990
PT - Article
AB - A new elasto-plastic study of the contact between the helix and the rods of  the delay line of Traveling Waves Tubes (TWT) was realized. Our study is  focused on the analysis of the hot lines shrinking phenomenon. In the  studied case, unlike brazed configuration, the contact areas are not  perfect, resulting in a diminution of the heat transfer process. In order to  maximize the contact area and to homogenize the contact pressure, a soft  thermal conductive material is coated on the helix: copper was chosen for  this study. In the present work, an analytical model is used to identify the  properties of the copper coating at a given temperature. We focused on the  mechanical properties in order to improve the assembly process with a better  numerical study. Experimental method have been made to validate the proposed  model. The first comparison results seem to indicate that the model  represents the reality with a good agreement. It is very clearly shown that  the temperature decreases the mechanical properties. (Young’s modulus, yield  strength, tensile strength…). And the thickness of the coating increases the  contact area. This last point is less important at room temperature (6% of  increase) than at 140°C (22%).