fitting curve to custom equation

I want to use Johnson-Cook equation, so, I have experiment data about three strain rate. (0.001, 1000, 2000) equation : y=(A+B*x^N)*(1+C*log(strain rate))
I should find A, B, C and N from curve fitting. But with the curve fitting toolbox, I got wrong answer.
In this case, how can I fit the curve?

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dpb
dpb 2017년 6월 22일
Can't estimate four parameters with only three data points, sorry. You could choose a value for one of the three but would still have no extra DOF so if there's any noise in the acquired data the model estimated could be expected to be less than desirable.

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카테고리

도움말 센터File Exchange에서 Curve Fitting Toolbox 시작하기에 대해 자세히 알아보기

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2017년 6월 22일

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dpb
2017년 6월 22일

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