PTR2 口试(国外英文资料).doc

PTR2 口试(国外英文资料) The second stage of oral exams The sixth chapter (ren pumping 2 questions) 1. metal in the material composition is generally divided into several categories? What are the basic properties of the metal? (1) metal according to its composition can be divided into two categories of pure metals and alloys. (5 points) (2) the basic properties of metals include physical properties, chemical properties, mechanical properties and process performance. (5 points) 2. at present in the civil transport, honeycomb sandwich structure is mainly used for which position? (1) under local aerodynamic load function from the rectifier components, such as engine nacelle, the rectifier, the leading edge of the wing, wing tip rectifier, etc.; (4) (2) the installation of rectifying communication navigation on the antenna (3); (3) smaller stress control surface and an adjusting plate, such as rudder, flaps, spoilers, adjusting plate. (3 points) What is the use of 3. sealants? (answer 5 can) (*) (1) in the mixed sealant after, should be used as soon as possible or stored at low temperature. Different sealants with temperature and time period applying different and cold preservation requirements, must pay attention to. (2 points) (2) the sealant curing time varies with the ambient temperature and humidity. If the temperature is lower than 60oF, curing treatment will be particularly slow, for most of the sealant, the temperature at 77oF, relative humidity is the most ideal curing environment in 50%. (2 points) (3) in order to accelerate the curing sealant, can be heated by method of infrared irradiation or hot air blowing, but the temperature is not more than 120oF. Used to heat the air must be filtered to remove the moisture in the air and dust. (2 points) (4) are installed in a sealant application interface, there must be a permanent or temporary fixture to maintain close contact on the interface in the process of curing sealant, and do not allow for heating during the curing pr