Numerical studies of magnetostriction in post-tensioning tendon system based on finite element analysis

Abstract

PT tendon system is important elements in terms of service and safety in prestressed concrete structure. The tensile force monitoring in PT tendon system by eddy current technique measures the changes of magnetic flux on the wedge surface under different tensile force by magnetostriction. This thesis presents a numerical analysis of PT tendon system to estimate the magnetic flux density under different stress condition. The magnetic material properties are achieved by material properties test using MTS machine, and Three dimensional model of a pre-stressing strand, a wedge, and a barrel are developed. Variation of stress distribution and magnetic flux density are observed using commercial numerical simulation program, ABAQUS. Then, laboratory experiments are carried out to evaluate tensile force loss of a 3.3 m long pre-stressing strand. The monotonic relationship between tendon force loss and magnetic flux density is successfully observed.