# IB Physics Extended Essay – Grade A (30/34)

IB 2020 May Session 에서 A (30/34) 를 받은 Physics Extended Essay 입니다.

주제는 Pendulum Tuned Mass Damper 로, “What is the optimum length and mass of Pendulum Tuned Mass Damper in damping the horizontal oscillations of the building?” 라는 Research Question 을 중심으로 에세이를 작성했습니다.

흔히 물리, 화학 등 과학 과목의 EE는 A점수를 받기 힘든 것으로 알려져 있지만, 본인이 흥미있는 주제로 선정하고 착실히 실험을 해 나가다보면 충분히 좋은 점수를 획득할 수 있습니다. 제 에세이가 과학 과목으로 EE를 작성하고는 싶지만 낮은 점수를 받을까 두려운 분들에게 좋은 가이드가 되기를 바랍니다.

[목차]

[본문내용]

### Introduction:

The global population keeps increasing at an accelerating rate, which led the skyscrapers to be built all around the world (such as Taipei 101 tower and Burj Khalifa) as tall buildings allow more free space for use in smaller area of land. However, these skyscrapers are subject to oscillatory movements due to force exerted by wind, earthquake, and so on. Damping means reduction of mechanical oscillations and other types of vibrations through dissipating the energy
. All buildings have inherent damping such as from friction, which gradually dampens the motion of the building. However, one device that can be added to buildings to more effectively damp those oscillatory motions is called Tuned Mass Damper (TMD). TMD’s inertia exerts counter-force to the building’s oscillation and dissipates the building’s kinetic energy3, effectively and quickly reducing the oscillation amplitudes.

Among various types of TMDs, this investigation focuses on passive PTMD (pendulum TMD), where passive indicates that TMD is independent of external energy sources.

As a simplified version of real-world phenomena, this investigation focuses on free, damped vibrations of SDOF (single-degree-of-freedom, where one coordinate is required to pinpoint the position of the system at any time) system, where both model and PTMD are damped (free vibration indicates that only an initial force is exerted and then the object is let alone to vibrate).

PTMDs are identified by three main parameters: length that governs frequency, mass that is directly related to inertia, and damping ratio (a dimensionless value that shows the effectiveness of damping device in dissipating energy). Due to resource constraint, damping ratio is not able to be numerically manipulated in this investigation, and is maintained as control variable. Hence, the two independent variables of this investigation are the length and mass of PTMD. An SDOF model building and PTMD are built, and damping effect is tested for various lengths and mass ratios by measuring the horizontal displacements of model throughout the progress of oscillations (for 20 seconds) using Tracker software…

• 총 페이지수: 55 pages
• 과목명: Physics
• 주제: What is the optimum length and mass of Pendulum Tuned Mass Damper in damping the horizontal oscillations of the building?
• The file is in PDF format.