VIBRATION
VIBRATION
Embedded Files
Summary
Vibration is a mechanical movement around an equilibrium point. Vibration is generally detrimental to most mechanical systems and even to humans, although it is used in several engineering fields such as defect identification, new machine inspection, and machine quality control. The transmission of vibration to structure and equipment results in physical damage, degradation, structural instability, etc. Short- and long-term exposure to vibration also causes human health problems. Vibration should therefore be controlled and reduced to protect the structural integrity and functionality of mechanical systems. Whether the vibration involves automobiles, aircraft, human being, or the change of economic indicators, the study of vibration can be effectively used to gain insight and understanding. Our laboratory is committed to the study of vibration. Some key projects of research are as follows.
Mechanical low-pass filters for high-g accelerometers
Understanding the vibration-absorbing behavior of polymers is crucial to a range of vibration damping applications. Here, we present a systematic method to estimate the low-pass filtering characteristics of thin polymer plates by combining fractional derivative standard linear solid (FDSLS) model for describing the frequency-dependent dynamic modulus of polymers measured by dynamic mechanical analysis (DMA), one-phase exponential growth function for expressing the shape factor dependence of the dynamic modulus, and harmonic base excitation in a single degree of freedom (SDOF) damped system. The proposed method makes an accurate estimation on the low-pass filtering characteristics (i.e., displacement transmissibility and cut-off frequency) of thin polymer plates with acceptable and non-significant error. The findings will enhance comprehension of solid polymer mechanics and support the progress of vibration protection for microelectromechanical systems (MEMS) devices using thin polymer plates.
Researcher funders and partners
National Research Foundation of Korea (NRF), Agency for Defense Development (ADD), Korea Advanced Institute of Science and Technology (KAIST), JMJ Korea
Inertial igniters for small thermal batteries
A class of fully mechanical miniature inertial igniters are developed to activate thermal batteries for gun-fired munitions and mortars using the acceleration experienced by the gun-fired munitions and mortars. The miniature inertial igniters do not ignite the percussion primer or pyrotechnic material of thermal batteries when the acceleration profile applied to the miniature inertial igniters corresponds to that of accidental drops, transportation, and handling. The miniature inertial igniters, however, always work when the acceleration profile is matched with that of gun-firing environment. Extensive dynamics modeling and model validation tests are made to design, fabrication, and characterize the fully mechanical miniature inertial igniters.
Researcher funders and partners
Agency for Defense Development (ADD), Korea Research Institute for Defense Technology Planning and Advancement (KRIT), VitzroMiltech
Page updated
Google Sites
Report abuse