發送短信 : Formulation of constitutive relations based on indentation test

 _    _    __   __   _    _    __   __   __   _   
| |  | ||  \ \\/ // | || | ||  \ \\/ // | || | || 
| |/\| ||   \ ` //  | || | ||   \ ` //  | '--' || 
|  /\  ||    | ||   | \\_/ ||    | ||   | .--. || 
|_// \_||    |_||    \____//     |_||   |_|| |_|| 
`-`   `-`    `-`'     `---`      `-`'   `-`  `-`