Tuesday, October 29, 2019
Mechanical Measurements Essay Example | Topics and Well Written Essays - 1000 words
Mechanical Measurements - Essay Example This technique is also sensitive to extreme temperatures because it affects the transition of the luminescent molecules (Mantel 2005). The PSP material is also used to develop coat for self adhesive tape and decals. This approach is preferable as itÃ¢â¬â¢s quick and easy during experimentation. ItÃ¢â¬â¢s also reduces the time consumed for surface preparation as well as cost minimization (Mantel 2005). Pressure sensitive paint technique is also used in wind tunnels for pressure management. Due to the ability of this technique to provide field management, it produces global surface maps with better resolutions. Producing high quality global surface maps however requires a clear understanding of the e internal mechanisms of the technique as well as the functions, properties and experimental setup (Sullivan & Liu 2004). This technique has been found to be easier, more accurate faster and cost effective as compared to the use of pressure ports and computational fluid dynamics for exte rnal pressure management. ... mage illustrates the parts of the pressure sensitive paint device The pressure sensitive paint is made up of luminescent molecules that are distributed in an oxygen permeable polymer binder. When the PSP is exposed to ultraviolet rays, it causes the luminescent molecules to gain a higher energy state. In this state the molecules can decay is several ways such as shifting the energy to the polymer binder, conflicting with the oxygen molecules on the PSP surface and discharging the light (Mantel 2005). The luminescent molecules are sensitive to oxygen molecules therefore when they collide with the oxygen molecules, they react to produce light. The produced light is inversely proportional to the amount of oxygen molecules available on the surface. Most of the collisions between the luminescent molecules and oxygen occur when the PSP is under a lot of pressure, therefore the amount of light emitted is inversely proportional to the pressure on the surface. Hence the pressure on the surfac e is easily calculated from the amount of light emitted. However, the challenge with the luminescent molecules transferring the energy to the polymer binder is that the energy transfer requires increase in temperature therefore causing the temperature on the PSP surface to rise (Mantel 2005). This affects the ability of the luminescent molecules to react with oxygen and could lead to release of inaccurate results. The effects of the temperature rise are slight because in most cases the temperature rises by a few degrees. The use of PSP could also be challenging because of the nature of experiments and high level of sensitivity. Fig 2 schematic diagram of pressure-sensitive paint measurement system TheÃ Moire?Ã techniqueÃ forÃ stress/strainÃ analysis The moire technique is used to determine
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