Composite gas turbine engine component

A rotor assembly for a gas turbine engine comprising:

• a rotatable hub extending along a longitudinal axis and carrying an array of airfoils;
• an array of platforms, each one of the platforms defining a gas path surface between adjacent airfoils of the array of airfoils, and wherein each of the platforms comprises:
• first, second and third platform cores;
• a composite wrap defining a platform body and a plurality of platform flanges that mount the platform to the hub, and the composite wrap extending about a perimeter of the first, second and third platform cores;
• and
• a plurality of internal ribs that divide the internal cavity into first, second and third compartments that receive respective ones of the first, second and third platform cores such that the first and third platform cores are axially aligned with the plurality of flanges and such that the second platform core is spaced apart axially from the plurality of flanges with respect to the longitudinal axis.

A gas turbine engine comprising:

• a fan section;
• a compressor section;
• a turbine section that drives the fan section and the compressor section;
• and
• a rotor assembly comprising:
• a hub rotatable about an engine longitudinal axis, the hub including a plurality of flanges;
• an array of airfoils circumferentially distributed about an outer periphery of the hub, each one of the airfoils including an airfoil section extending from a root section mounted to the hub;
• an array of platforms circumferentially distributed about the outer periphery of the hub to define an inner gas path boundary between adjacent airfoils of the array of airfoils, and each of the platforms comprising:
• at least one honeycomb core including a plurality of cells;
• and
• a composite wrap extending about the at least one honeycomb core to define a plurality of platform flanges;
• and
• a plurality of retention pins, each one of the retention pins extending through the flanges of the hub and through the platform flanges of a respective one of the platforms to mechanically attach the respective one of the platforms to the hub.