| 摘要 |
PROBLEM TO BE SOLVED: To easily and accurately measure a coefficient of elasticity and resistance, by obtaining an inflection point on a tertiary regression curve that is approximated to distortion and stress, and obtaining the characteristics of a material test piece based on a primary regression straight line with an inflection point as a connection point. SOLUTION: While a pull load is being applied to a material test piece using a material testing machine body 1, a load (p) and a growthλbeing applied to a test piece are detected by a load detector 2 and a growth detector 3. Then, they are converted to digital data via A/D converters 2a and 3a and are taken into a CPU 5. The CPU 5 obtains a tertiary regression curve expression for approximating the load growth characteristics with the growthλand the load (p) as an independent variable (x) and a subsidiary variable (y) by an operation means 5a using a program being stored in a ROM 4. Then, an operation means 5b obtains a primary regression straight line with the inflection point being obtained on the tertiary regression curve expression as a connection point, an operation means 5c obtains the coefficient of elasticity and resistance of the test piece based on the primary regression straight line and displays them on a display 7, for example, of a CRT.
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