All entries for Monday 20 January 2014
January 20, 2014
After one week break, it was a good beginning with Design for X. Design for X can be seen as a design for everything such as design for manufacturability or design for environment. For instance, if we assume that we are dealing with a project which is about manufacturing a water pump. We can categorize our design aims into different categories just I did as above. Actually this module provides us how much design has a role or impact on innovation. Yes, I will call it innovation! DesignX looks the project from different perspectives of views. For instance, not only covering the issues about serviceability or reliability of product in future, but also may include design for environment. Actually, DesignX wants to show that designing a product is not just manufacturing the product, but also being ready to following issues.
In today’s case study was about an aircraft crash in 1989. As a mechanical engineer, I exited about both today’s topic and case study, because I am very familiar with this topic and I have been doing this kind of analysis more than 5 years. The video showed us that due to explosion at the tail engine, hydraulic system was lost. With pilot’s outstanding exertion, 185 people were survived surprisingly, even 111 people died.
According to our team’s great investigation and my interpretation, due to lack of know-how of one more vacuuming process which is called triple-vacuum process in the beg-70s, the melted titanium reacted with air and had impurities in its micro-structure. These impurities caused cracks on the edge of fan disk which could be seen minor issues on those days, when the engine was freshly manufactured by GE. However, cracks can propagate over time due to fluctuating pressure levels and then reduced the strength of parts furtively. Even though engineers estimated fatigue life (useful life) of engine 25, it suddenly exploded in 17th year and gave damage to hydraulic system. Second major design failure was that there was no back-up hydraulic system that can be operated in case of emergency. Actually, nowadays aircraft are supposed to be checked by ultrasonic devices in order to prevent any fatigue problems and the aircrafts have 3 have hydraulic systems.