Blade Stress Calculations - Mode Deflection vs. Force Integration

Two methods for calculating blade stresses from aeroelastic responses, mode deflection and force integration, are described and compared with respect to accuracy and ease of operational usage. Analytic results are presented for a realistic bearingless helicopter rotor configuration which is capable of experiencing concentrated shears and moments at discreate spanwise points on the blade. It is generally conclud.ed that, when properly implemented, the force integration method yields more reliably accurate stress calculations.