Identifying　the　weak　stiffness　positions　of　a　machine　tool　is　crucial　for　enhancing　its　overall　structural　rigidity.　In　1high-value　engineering　structures　such　as　machine　tools　or　aviation　fields,　generating　the　data　first　by　simulation　is　often　necessary.　Thus,　the　required　model　often　corresponds　to　the　actual　working　conditions.　However,　achieving　an　equal　spacing　sensor　distribution　during　the　actual　measurement　process　in　the　actual　damage　identification　project　is　often　difficult　because　of　the　occlusion　of　the　sensor　position　arranged　by　the　measured　structure.　In　damage　identification,　the　identification　indexes　designed　by　equidistant　sensor　distribution　often　fail　or　have　large　errors.　In　this　study,　a　damage　identification　index　(ae　＇＇)　method　independent　of　the　distribution　of　equidistant　sensors　is　proposed　based　on　the　flexibility　curvature　matrix.　The　element　stiffness　matrix　and　the　element　mass　matrix　for　solving　the　flexibility　curvature　matrix　are　adjusted　according　to　the　actual　sensor　spacing,　and　the　obtained　flexibility　matrix　is　calculated　twice　by　difference　to　obtain　a　new　damage　identification　index.　A　cantilever　beam　is　employed　as　a　reference　to　confirm　the　efficacy　of　the　damage　identification　index　via　numerical　simulation.　Thus,　the　robustness　of　this　damage　identification　index　in　identifying　damage　across　various　scenarios　of　damage　and　amidst　noise　interference　is　demonstrated.　Further　validation　of　the　index　utility　is　conducted　on　a　gear　grinding　machine,　thereby　confirming　its　adaptability　even　with　sensors　spaced　unevenly.