Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Comparative study between galvanized and stainless steel applied in industrial equipments under dynamic and nonlinear behavior
Submission Author:
Paulo Almir Borges de Sousa Filho , SP
Co-Authors:
Paulo Almir Borges de Sousa Filho, Jose Rubert
Presenter: Paulo Almir Borges de Sousa Filho
doi://10.26678/ABCM.COBEM2021.COB2021-0362
Abstract
The current investigation is focused on the evaluation of different materials applied in steel structures builds for cooling tower equipments, in this case stainless and galvanized steel. These equipments are largely found in industries, e.g. sugarcane, most utilized for temperature maintenance and control of processes and can be arranged in single or multi cells. The drive systems are usually composed by an electrical motor coupled to a speed reducer associated with a propeller. Due to process fluid properties the structural components can be exposed to corrosion. This alongside with vibrations derived from the drive system can lead to failure. It becomes necessary analyze the structural integrity under different condition entries verifying critical points and overall displacements, loads and stresses. The analysis is based on the stiffness method using three-dimensional truss elements, with static and dynamic modules. For the time dependent part, the Newmark’s algorithm is applied with parameters chosen so the system is unconditionally stable regardless the time step adopted. Lumped mass matrices for space truss elements are used to describe the effects associated to mass in the dynamic analysis. Spring element models are also implemented to allow further possible changes in the structure geometry. An elastic-linear work hardening constitutive model is used to describe the elasto-plastic behavior of the materials. A homogeneous reduction in the cross-section area was considered for the elements under corrosion. For the numerical analysis, nonlinear finite element codes were written in FORTRAN language in Linux-Ubuntu environment. Examples from the literature were analyzed to verify the accuracy of the results from the routines simulations. For the study-case the input loads were based on data collected over reliability and predictive maintenance field software. Both static and dynamic analysis are executed, first considering non-corroded galvanized and stainless steel elements. The same procedure is repeated, this time considering uniform corrosion along elements. The main results are presented, stablishing a comparison between the effects related to nonlinearities and overall structure response for both materials.
Keywords
nonlinear dynamics, geometric nonlinearity, Physical Nonlinearity, Computational simulation, Steel Structures, corrosion
