Systems and methods for compacting components are provided. In one exemplary aspect, a component is positioned between a first tool portion and a second tool portion of a compaction tool. A sandwich structure is positioned between the first tool portion and the component. The sandwich structure includes a thermally expandable material and a rigid shell. The thermally expandable material is positioned between the first tool portion and the rigid shell. During compaction, the thermally expandable material is subjected to elevated temperatures and pressures, e.g., within an autoclave. When subjected to elevated temperatures and pressures, the thermally expandable material applies a force on the rigid shell, which in turn applies a force on the component so as to compact the component between the rigid shell and the second tool portion.