[知识面拓展] 航空材料基础知识

航空材料基础
结构车间
Proper identification of the aircraft structural material is the first step in ensuring that the continuing airworthiness of the aircraft will not be degraded by making an improper repair using the wrong materials.

对航空器结构材料的正确辩识是确保不会因为在维修过程中使用不恰当的材料而影响航空器适航性的首要因素
Repair materials can be divided into sheet metal materials, extrusions ,formed sections and bars, also, divided into metallic and nonmetallic materials. We will learn the basic knowledge and characteristics of repair materials generally, for further use of these materials.

修理材料可分为板材，挤压型材，板弯型材和棒料等,也可分为金属和非金属材料。在本章中，我们将大概地学习有关修理材料的基本知识和特点，为以后我们更好地应用这些材料打好基础。
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金属材料替代
Principle(原则) ：
The first and most important of substitution is maintaining the original strength of the structure
  首先也是最重要的是保证原始结构的强度
The others:
•maintaining contour or aerodynamic smoothness
  保持外形或空气动力学的平滑性
•maintaining original weight if possible or keeping added weight to a minimum
如果可能保持原始重量或尽可能少的增加中重量
•maintaining the original corrosion resistant properties of the metal
  保持原始的抗腐蚀性能
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优点：
较大的弯曲刚度和弯曲强度。
较好的吸声和隔热隔声性能；较高的乃声波疲劳性能。
光滑的气动外形，气密性较好。
缺点：
发生损伤不容易修理和更换，大开口设计比较困难
抗湿热环境能力差