Dynamics of Cracked Viscoelastic Beam: An Operator Based Finite Element Approach

Autor: Krishanu Ganguly, Pradeep Nahak, H. Roy
Rok vydání: 2017
Předmět:
Zdroj: Volume 2: Structures and Dynamics; Renewable Energy (Solar, Wind); Inlets and Exhausts; Emerging Technologies (Hybrid Electric Propulsion, UAV, ...); GT Operation and Maintenance; Materials and Manufacturing (Including Coatings, Composites, CMCs, Additive Manufacturing); Analytics and Digital Solutions for Gas Turbines/Rotating Machinery.
DOI: 10.1115/gtindia2017-4616
Popis: The presence of crack introduces local flexibilities and changes physical characteristics of a structure which in turn alter its dynamic behavior. Crack depth, location, orientation and number of cracks are the main parameters that greatly influence the dynamics. Therefore, it is necessary to understand dynamics of cracked structures. Predominantly, every material may be treated as viscoelastic and most of the time material damping facilitates to suppress vibration. Thus present study concentrates on exploring the dynamic behavior of damped cantilever beam with single open crack. Operator based constitutive relationship is used to develop the general time domain, linear viscoelastic model. Higher order equation of motion is obtained based on Euler-Bernoulli and Timoshenko beam theory. Finite element method is utilized to discretize the continuum. Higher order equation is further converted to state space form for Eigen analysis. From the numerical results, it is observed that the appearance of crack decreases the natural frequency of vibration when compared to an uncracked viscoelastic beam. Under cracked conditions, the viscoelastic Timoshenko beam tends to give lower frequency values when compared to viscoelastic Euler-Bernoulli beam due to shear effect.
Databáze: OpenAIRE