Stability and accuracy of Wilson-θ method with load modification
Received:October 16, 2010  Revised:May 18, 2011
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DOI:10.7511/jslx20122008
KeyWord:Wilson-θ method  stability  calculation accuracy  load modification  spectral radius
  
AuthorInstitution
方德平 华侨大学 土木工程学院, 泉州
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Abstract:
      The displacement,velocity and acceleration obtained by Wilson-θ method don’t meet the dynamic equilibrium equations at the time t.Wilson-θ method with load modification is put forward,that is,a load δF(t) is added to meet the dynamic equilibrium equations at the time t,then the load modification - θ'δF(t) is added into calculation as load at the time t+ Δt,when θ' = 0,Wilson-θ method with load modification returns to Wilson-θ method.On condition of unconditional stability,the range of θ value is different for different values of θ'.The calculation error is defined in time-stepping method,the calculation results indicate:positive correlation exists between the calculation error and θ value; for θ' = 0.6,θ value with unconditional stability is minimum 1.24,therefore,the calculation error for θ'=0.6,θ=1.24 is minimum,which is suggested to be used in calculation.Maintaining the unconditional stability,almost not increasing the calculation quantity,Wilson-θ method with load modification can improve the calculation accuracy.