Annular spring for a bearing assembly of a gas turbine engine

A bearing compartment for a gas turbine engine, comprising:

• a bearing support static structure;
• a bearing assembly radially inboard of the bearing support static structure;
• an oil film damper radially between the bearing assembly and the bearing support static structure;
• an annular first spring radially between the bearing assembly and the bearing support static structure;
• and
• an annular second spring radially between the bearing assembly and the bearing support static structure, the second spring including a multiple of ligaments, an inner support ring and an outer support ring;
• wherein a first of the multiple of ligaments is configured to form a first indentation and a second indentation, the first indentation extends radially inward to a first indentation end defined by the first of the multiple of ligaments, and the second indentation extends radially outward to a second indentation end defined by the first of the multiple of ligaments;
• wherein the first of the multiple of ligaments consists of a first end segment, a second end segment and an intermediate segment disposed circumferentially between the first end segment and the second end segment;
• wherein the second end segment projects substantially radially in from the outer support ring, and partially defines the first indentation;
• wherein the first end segment projects substantially radially out from the inner support ring, and partially defines the second indentation;
• wherein the oil film damper comprises a first flange, a second flange and a center portion projecting radially outward from the first flange and the second flange;
• wherein the center portion is disposed axially between the annular first spring and the annular second spring;
• wherein the annular first spring is supported by the first flange;
• and
• wherein the annular second spring is supported by the second flange.

A method, comprising:

• locating an annular first spring radially between an oil film damper and a bearing support static structure, the first spring including a multiple of ligaments, an inner support and an outer support;
• and
• locating an annular second spring radially between the oil film damper and the bearing support static structure, a center portion of the oil film damper axially separating the annular first spring from the annular second spring;
• wherein a first of the multiple of ligaments is configured with a first recess and a second recess, the first recess has a first open end and a first closed end formed by a first surface of the first of the multiple of ligaments, the first recess extends radially inward from the first open end to the first closed end, the second recess has a second open end and a second closed end formed by a second surface of the first of the multiple of ligaments, and the second recess extends radially outward from the second open end to the second closed end;
• wherein the first of the multiple of ligaments consists of a first end segment, a second end segment and an intermediate segment completely circumferentially between the first end segment and the second end segment;
• wherein the second end segment projects substantially radially in from the outer support, and partially defines the first recess;
• wherein the first end segment projects substantially radially out from the inner support, and partially defines the second recess;
• wherein the oil film damper comprises a first flange, a second flange and the center portion which projects radially outward from the first flange and the second flange;
• wherein the center portion is axially between the annular first spring and the annular second spring;
• wherein the annular first spring is supported by the first flange;
• and
• wherein the annular second spring is supported by the second flange.