Anisotropy refers to the property of materials or structures to exhibit different responses in different directions. In vibration testing, regardless of the type of excitation, the test specimen always shows characteristics of anisotropy due to the multi-directional structural response. This is crucial in determining the control scheme for vibration testing.
Mapping, on the other hand, refers to the transmission of vibration excitation from the vibration table to the fixture, and then to the test specimen. This transmission process is tightly connected, and the response generated by the specimen and fixture is simultaneously fed back to the fixture and table, creating a reverse mapping effect. Understanding this concept is important when discussing vibration test control and fixtures.
In summary, vibration testing involves the interaction between the three components of the vibration table, fixture, and test specimen. Different mechanical impedances exist along different transmission paths. If the vibration excitation simulation by the table is realistic but the fixture introduces its own response during the test, the response characteristics of the product in vibration testing may not perfectly match its actual operating state. This is an important factor that affects the authenticity and effectiveness of laboratory vibration simulation testing.
