NIE Guanglin, BAO Yiwang, WAN Detian
(State Key Laboratory of Green Building Materials, China Building Materials Academy Co., Ltd., Beijing 100024, China)

Abstract: Tube is a kind of significant form of material product structure, and the accurate evaluation of the tube mechanical properties is crucially important for insuring the service safety and reliability of the tube components. The presented split ring method provides feasible solution to the determination of tube mechanical properties, but the formulas for calculating the elastic modulus and bending strength apply only to the thin-walled tubes. To determine the mechanical properties of thick-walled tubes accurately, the general split ring method with wider application range was proposed in this study based on the analytical theory for curved bar, by taking into account the effect of the radial and tangential forces on the strain energy of the tube sample. The three-point bending method was used to test the elastic modulus (72.08±1.87 GPa) and bending strength (73.84±6.67 MPa) of the quartz glass beams, and the test result can be used as the reference data. Both the split ring method and general split ring method were used to determine the elastic modulus and bendingstrength of the same quartz glass tubes. The test results indicate that the relative deviation between the measured data by split ring method and general split ring method gradually increased with the rising wall thickness of the tube samples. The elastic modulus and bending strength tested by the general split ring method were closer to the test results by three-point bending method, i.e., the results measured by the general split ring method were more accurate. And the general split ring method can be used to determine the mechanical properties for both the thin-walled and thick-walled tubes.

Key words: tube; elastic modulus; bending strength; split ring method; general split ring method