Composite materials should be reasonable in design, otherwise they will be destroyed prematurely

Complex failure modes are different from isotropic materials such as metals. The aluminum foil food packaging bag is also a composite of aluminum sheet and plastic. Because of the fiber, the composite material is not easy to tear on only one surface, there is no high resistance to the ascent of many metals, and if the pressure is not applied in the direction intended by the design, the composite material will be destroyed prematurely. Just as useful structures in food packaging bags are constructed of ductile materials such as rigid or aluminum, which have a fairly good fixing strength. This allows the designer to correctly understand and determine safety factors that provide some assurance that the structure of the food pouch will not be damaged during use.

Due to the requirements of the environment, it has become necessary to use fragile materials such as glass and ceramics in practical structural designs to utilize their special properties such as high temperature and high temperature. When these fragile materials are used in a century-old structure, designers still need to ensure that the structure will not be damaged prematurely.