Digital device and method for measuring the axial load of a torque-shear-type high strength bolt

A method for measuring an axial load of a torque-shear-type high strength bolt, comprising:

• the first step of obtaining an accumulated current amount from an electromotive wrench fastening a torque-shear-type high strength bolt until a pintail of the torque-shear-type high strength bolt is fractured;
• the second step comprising the step of measuring an axial load of the torque-shear-type high strength bolt according to a normal condition and abnormal conditions, the step of quantifying the axial load by weighting the axial load measured according to the conditions;
• and the step of searching the accumulated current amount in a one-to-one relationship with the axial load;
• the third step comprising the step of setting a maximum current amount, at a time point when the pintail of the torque-shear-type high strength bolt is fractured, as a reference value, and sampling data by quantifying the accumulated current amount into equal divisions in a unit of 10%, the step of applying variance analysis to the axial load and accumulated current amount quantified at the second step through a statistical management method, and the step of calculating a regression analysis estimating expression between the value obtained by integrating the data and the axial load;
• and
• the fourth step of estimating the axial load from the accumulated current amount through the regression analysis estimating expression.