홍석윤 교수

In this paper, an energy flow model is developed to analyze transverse vibration including the effects of rotatory inertia as well as shear distortion, which are very important in the Timoshenko beam transversely vibrating in the medium‐to‐high frequency ranges. The energy governing equations for this energy flow model are newly derived by using classical displacement solutions of the flexural motion for the Timoshenko beam, in detail. The derived energy governing equations are in the general fo

This paper presents the methodology for the energy flow analysis of coupled Timoshenko beam structures and various numerical applications to verify the developed methodology. To extend the application of the energy flow model for corrected flexural waves in the Timoshenko beam, which is developed in the other companion paper, to coupled structures, the wave transmission analyses of general coupled Timoshenko beam systems are performed. First, power transmission and reflection coefficients for al

With the approximately normalized eigenfunctions and matching modal equations obtained in a differential form, we have implemented the structural vibration control successfully. In applying the steady-state quadratic coupled mode optimal control algorithm for the control structure, i.e. the all-clamped square plate, the non-orthogonalized extra terms are evaluated. By the suitable formulation of a control system, we could simulate the modal responses of the first six modes showing the validity o

In this paper energy flow models for the transverse vibration of finite orthotropic plates are developed. These models are expressed with time‐ and locally space‐averaged far‐field energy density, and show more general forms than the conventional EFA models for isotropic plates. To verify the accuracy of the developed models, numerical analyses are performed for finite rectangular plates vibrating at a single frequency, and the calculated results expressed with the energy and intensity levels ar

In this paper, Energy Flow Boundary Element Method (EFBEM) was developed to predict the vibration behavior of one‐ and two‐dimensional structures in the medium‐to‐high frequency ranges. Free Space Green functions used in the method were obtained from EFA energy equations. Direct and indirect EFBEMs were formulated for both one‐ and two‐dimensional cases, and numerically applied to predict the energy density and intensity distributions of simple Euler‐Bernoulli beams, single rectangular thin plat

Our work aims to find a general solution for the vibrational energy flow through a plane network of beams on the basis of an energy flow analysis. A joint between two semi‐infinite beams are modeled by three sets of springs and dashpots. Thus, the results can incorporate the case of complaint and non‐conservative in all the three degrees of freedom. In the cases of finite coupled structures connected at a certain angle, the derived non‐conservative joints and developed wave energy equation were

The stealth performance of submarines is closely related to their hull forms. In this study, an optimization method based on deep reinforcement learning (DRL) was developed to design submarine hull forms, aimed at maximizing the stealth performance. The DRL optimization technique relied on the decision-making process of an agent for determining actions resulting in changes in the hull form, using stealth performance as the reward. The stealth performance of the submarine was evaluated through a