Torsional guided wave inspection is widely used for pipeline inspection. Most commonly piezoelectric and
magnetostrictive transducers are used to generate torsional guided waves. These types of transducers require bonding
or mechanical contact to the pipe which can result in changes over time which are undesirable for Structural Health
Monitoring. This paper presents a non-contact Lorentz force based Electromagnetic Acoustic Transducer for torsional
guided wave monitoring of pipelines. First, the excitation mechanism of the transducer is simulated by analyzing the
eddy current and the static magnetic field using the finite element method. An EMAT transformer model is presented
which describes the eddy current generation transfer function and the ultrasound excitation. Independently simulated
eddy current and magnetic fields are used to calculate the Lorentz force that an EMAT array induces on the surface of
a 3 inch schedule 40 pipe and an explicit finite element solver is then used to simulate the elastic wave propagation
in the pipe. Then, the reception mechanism and the expected received signal levels are discussed. The construction
of an experimental transducer is described and measurement results from the transducer setup are presented. The
measured and modeled performance agree well. Finally, a monitoring example is presented where an artificial defect
with 3% reflection coefficient is introduced and successfully detected with the designed sensor.