Theoretical response of a simply supported beam with a strain rate dependant modulus to a moving load

• The response of a beam made of viscoelastic material to a moving load is investigated.
• The ‘dynamic’ modulus is assumed to be related to strain rate.
• Variation in strain throughout the beam is analyzed for each position of the moving load.
• The significance of using a ‘dynamic’ modulus becomes more evident for high speeds and loads.
• The dynamic amplification factor of a beam is shown to be particularly sensitive to a strain rate dependant material.

Moving load problems typically consider a structural material with properties that do not vary while the load traverses the structure. However, there is evidence that for some materials the structure will respond with a higher modulus of elasticity than that corresponding to a static test for sufficiently high strain rates. This paper investigates the variation in strain rate of a simply supported beam made of a viscoelastic material traversed by a moving load and its effect on the modulus of elasticity. The influence of speed and magnitude of the moving load on the displacement and strain responses of the beam is discussed.