Final answer:
The minimum displacement of baseline tubes in a 3-point bending test is not explicitly stated, but it refers to the deflection a material undergoes during the test and is critical for comparing material properties.
Step-by-step explanation:
The question pertains to the minimum displacement of baseline tubes in a 3-point bending test, often conducted in materials science and engineering. This test is also known as a flexural test and is used to determine the flexural strength of a material. Although the exact minimum displacement for a baseline tube in such a test is not provided in the reference information, we can infer that this displacement is related to the fundamental frequency of the tube when subjected to a bending force. Typically, the minimum displacement is determined by the testing standards employed and the geometry of the tube, including factors like length and diameter. Displacement refers to the amount of deflection the tube undergoes during the test and will be monitored as a critical value for the comparison of material properties.