Hybrid Alloy Isogrid Engine Case for Thermal Expansion Control

The patent applies composite materials by combining titanium alloy for the wall with dissimilar alloy ribs (such as iron-nickel-cobalt or aluminum alloys). This composite construction allows each material to be selected for its optimal properties: titanium provides structural strength and heat resistance for the wall, while the dissimilar alloy ribs provide controlled thermal expansion characteristics. The differential thermal expansion between materials is managed through the specific material selection, reducing stress concentrations and maintaining clearance under thermal conditions.

The patent applies parameter changes by carefully selecting specific alloy compositions and their corresponding thermal expansion coefficients. The dissimilar alloy ribs are chosen to have thermal expansion properties that complement the titanium wall, creating a controlled differential expansion pattern. This parameter optimization allows the structure to manage thermal expansion effectively while maintaining manufacturability through established additive manufacturing processes for metal alloys.

The patent applies porous materials by implementing hollow ribs with internal cavities instead of solid ribs. These hollow ribs maintain sufficient structural strength while reducing mass and thermal inertia. The hollow configuration also reduces stress concentrations under thermal loading by distributing thermal stresses more evenly throughout the rib structure. The walls of the hollow ribs provide the necessary structural integrity while the empty interior reduces the overall stress burden during thermal cycling.