I want modeling fatigue steel railway bridge and a moving train is my load,do I need to enter my load to form cyclic? I do need some step or only one direct cyclic step is enough?
Example:
if we want to apply 1000 load cycles, the time period of each cycle is 0.25s.
Amplitude, as the term suggests, is just a scaling factor to the amount of load you wish to apply. So, instead of ramping up the load to the final value, if I wanted to have a triangular waveform, I could enter a table in the amplitude definition as follows:
Time | Amplitude
==================
0.0 | 0.0
_______________
0.5 | 0.5
_______________
1.0 | 0.0
So, if my ultimate load value is, say, 100 N, then at time=0.0, load=0.0*100=0.0. At time=0.5, load=0.5*100=50, ..
You can even assign a user defined loading protocol, if that's needed.
Example:
if we want to apply 1000 load cycles, the time period of each cycle is 0.25s.
Amplitude, as the term suggests, is just a scaling factor to the amount of load you wish to apply. So, instead of ramping up the load to the final value, if I wanted to have a triangular waveform, I could enter a table in the amplitude definition as follows:
Time | Amplitude
==================
0.0 | 0.0
_______________
0.5 | 0.5
_______________
1.0 | 0.0
So, if my ultimate load value is, say, 100 N, then at time=0.0, load=0.0*100=0.0. At time=0.5, load=0.5*100=50, ..
You can even assign a user defined loading protocol, if that's needed.
You can apply a waveform as ramps in such way to form a triangular waveform.
Other way is to apply the loading history by introducing constant increments of time, for each value of load, in a given period of time, until you reach the maximum load. Then you do it again, changing the sense of loading. You can enter this loading history by means of a table: time X load
This video tutorial gives good overview of Direct cyclic analysis in Abaqus.
https://www.youtube.com/watch?v=CDfwV-d4dLQ&index=3&list=PLE4jpqcRJiBrNlnkqCrCLJHKoIEs71mQP
Thanks for your answer.
I have a questions.
How can I apply a number of cycle?
For example, i want to apply the time period of each cycle is 1s and 10000 load cycle.
Hello, may I know..
if Direct Cyclic analysis is applied for Step 2, so what analysis should apply for Step 1?
Thank you
Dear Nazirah,
I'm not expert in the FCG topic, But I think you have to use a "General Static" analysis for step 1, and apply the initial loading in this step. The initial loading could be the minimum load in the fatigue analysis.
- Badges
- Science topic