Method for Predicting and Optimizing the Strength of Extruded Multi-Void Aluminum Heat Exchanger Tube

The mechanical response to internal pressure in extruded multi-void tube is investigated for three profiles using AA1050 alloy. Hydrostatic pressure data and changes in internal tube geometry are used to determine the effective stress in internal tube walls to instability (failure). True stress and strain data for internal walls in the tube are established and a model is proposed to predict the material response and pressure at failure. These data are compared to bulk material data from tensile testing. Differences in material response are attributed to stress state and size effects, and these mechanisms are reviewed. Process-structure-property relationships of extruded aluminum heat exchanger tube are also reviewed for brazed assemblies in light of the influence on size effects.