Defining a Fatigue Event Based on a Single Load To define a fatigue event based on a single load case, in the Add Event (Constant) PropertyManager: Set the Number of Cycles associated with the fatigue event. From the Loading Type menu , choose one of the following options: Fully reversed Zero based Load ratio In the Study Association box : Select a static, nonlinear or dynamic time history study in the first row. You can enter a scale factor under Scale. The program multiplies the stress components of the reference study by this factor to evaluate alternating stress values. For a nonlinear or dynamic time history study, under Step enter a particular time step. The output of this particular solution step is considered for the evaluation of alternating stress values. Click . Parent topicAdd Event (Constant) PropertyManager Defining a Fatigue Event Based on Multiple Load Cases Single Constant Amplitude Fatigue Event A constant amplitude fatigue event is fully defined by an alternating stress, mean stress (or stress ratio), and the number of loading cycles. Fully reversed The program sets the alternating stress at each node equal to the selected stress value (stress intensity, von Mises, or P1) from the reference static study times the scale factor. The maximum and minimum values of stress components are equal in magnitude and opposite in direction. Zero-based The program sets the alternating stress at each node equal to half the corresponding stress value in the reference static study times the scale factor. The program gets one of the peaks from the reference static study and sets the other peak to 0. User-defined load ratio Assuming that the user-defined load ratio is R, the program gets one of the peaks from the reference study (considering specified scale factor) and calculates the other peak by multiplying the first peak by R. The program then calculates the stress quantity selected in the Fatigue properties dialog box and calculates the alternating stress as |S*(1 - R)|/2 where S is the extreme value of the stress component in the reference static study.
Defining a Fatigue Event Based on a Single Load To define a fatigue event based on a single load case, in the Add Event (Constant) PropertyManager: Set the Number of Cycles associated with the fatigue event. From the Loading Type menu , choose one of the following options: Fully reversed Zero based Load ratio In the Study Association box : Select a static, nonlinear or dynamic time history study in the first row. You can enter a scale factor under Scale. The program multiplies the stress components of the reference study by this factor to evaluate alternating stress values. For a nonlinear or dynamic time history study, under Step enter a particular time step. The output of this particular solution step is considered for the evaluation of alternating stress values. Click . Parent topicAdd Event (Constant) PropertyManager Defining a Fatigue Event Based on Multiple Load Cases Single Constant Amplitude Fatigue Event A constant amplitude fatigue event is fully defined by an alternating stress, mean stress (or stress ratio), and the number of loading cycles. Fully reversed The program sets the alternating stress at each node equal to the selected stress value (stress intensity, von Mises, or P1) from the reference static study times the scale factor. The maximum and minimum values of stress components are equal in magnitude and opposite in direction. Zero-based The program sets the alternating stress at each node equal to half the corresponding stress value in the reference static study times the scale factor. The program gets one of the peaks from the reference static study and sets the other peak to 0. User-defined load ratio Assuming that the user-defined load ratio is R, the program gets one of the peaks from the reference study (considering specified scale factor) and calculates the other peak by multiplying the first peak by R. The program then calculates the stress quantity selected in the Fatigue properties dialog box and calculates the alternating stress as |S*(1 - R)|/2 where S is the extreme value of the stress component in the reference static study.
Single Constant Amplitude Fatigue Event A constant amplitude fatigue event is fully defined by an alternating stress, mean stress (or stress ratio), and the number of loading cycles. Fully reversed The program sets the alternating stress at each node equal to the selected stress value (stress intensity, von Mises, or P1) from the reference static study times the scale factor. The maximum and minimum values of stress components are equal in magnitude and opposite in direction. Zero-based The program sets the alternating stress at each node equal to half the corresponding stress value in the reference static study times the scale factor. The program gets one of the peaks from the reference static study and sets the other peak to 0. User-defined load ratio Assuming that the user-defined load ratio is R, the program gets one of the peaks from the reference study (considering specified scale factor) and calculates the other peak by multiplying the first peak by R. The program then calculates the stress quantity selected in the Fatigue properties dialog box and calculates the alternating stress as |S*(1 - R)|/2 where S is the extreme value of the stress component in the reference static study.