Abstract: The present invention relates to a method of calculating a fatigue usage factor, in a fatigue assessment on heating and cooling operation-transient states of a power plant, which is capable of correcting a stress intensity value under an actual operational condition by multiplying a stress intensity value, which is obtained in a design operational condition, by a stress intensity correction factor.

Abstract: The present invention relates to an apparatus and a method for calculating a fatigue usage factor with respect to fatigue generated in the material of a mechanical device depending upon changes of an operation environment during operation of the mechanical device. A fatigue usage factor UOP.cyc,transient n, which is based on the operation-transient state n, is calculated by multiplying a fatigue usage factor based on a design-transient state UDSGN.cyc,transient n by the value of a characteristic fatigue usage factor F (k) as shown in the following equation: UOP.cyc,transient n=F(k)×UDSGN.

Abstract: Disclosed are an apparatus and a method for calculating a temperature dependent Green's function using an appropriate weight function. The apparatus includes a material temperature change information input unit inputting change information of a material temperature; and a temperature dependent Green's function calculation unit receiving the change information of the material temperature through the material temperature change information input unit, calculating a temperature dependent Green's function using a weight function, and outputting the calculated result. According to aspects of embodiments, accuracy in the calculation of a thermal stress value can be improved by designing the weight function such that changes in physical properties of a material that change according to temperature changes are considered.

Abstract: The present invention relates to an apparatus and a method for calculating a fatigue usage factor with respect to fatigue generated in the material of a mechanical device depending upon changes of an operation environment during operation of the mechanical device. A fatigue usage factor UOP.cyc,transient n, which is based on the operation-transient state n, is calculated by multiplying a fatigue usage factor based on a design-transient state UDSGN.cyc,transient n by the value of a characteristic fatigue usage factor F (k) as shown in the following equation: UOP.cyc,transient n=F(k)×UDSGN.

Abstract: Disclosed are an apparatus and a method for calculating a temperature dependent Green's function using an appropriate weight function. The apparatus includes a material temperature change information input unit inputting change information of a material temperature; and a temperature dependent Green's function calculation unit receiving the change information of the material temperature through the material temperature change information input unit, calculating a temperature dependent Green's function using a weight function, and outputting the calculated result. According to aspects of embodiments, accuracy in the calculation of a thermal stress value can be improved by designing the weight function such that changes in physical properties of a material that change according to temperature changes are considered.