sammy3
Civil/Environmental
- Aug 8, 2006
- 7
Hello:
I have modelled a 3-D reinforced concrete column model in Abaqus. I have used the damaged plasticity concrete model and embedded truss elements for the rebar. My task is to develop a model that estimates the response of an RC column subjected to cyclic lateral loading. I've tried defining an amplitude function for my lateral displacement and running a General Static analysis; however there seems to be too much nonlinearity in the response (even with automatic stabilization) to run. So I took a second stab at the problem. I defined my first input file as a RIKS analysis and pushed the column to a specified lateral dispalcement. I then defined a second input file and restarted the previous analysis. In this retart analysis I defined a second RIKS step and pushed the column from its existing position to its conjugate displacement (0.2" in first input file to -0.2" in second input file). I continue this convention for all displacment cycles defined in my load protocol. I've testing this analysis procedure against experiemental results in the literature and my analytical results predict the behavior very well for low displacement magnitudes. However, I can't get all the way through the load protocol because I run into a problem where the RIKS step starts going in the wrong direction once my displacment magnitude starts to get larger. For instance, lets say I ended the previous RIKS step at a lateral displacement of 0.58". The next restart analysis defines a new RIKS step where I ask it to push the column to -0.58". If I try to do this the analysis gets to about -0.42" then it starts going toward zero again and all the way back up to 0.5". Finally it gives me an error stating that it reached a zero displacement increment and cannot finish the analysis. When I define the restart analysis and define a new RIKS step, I redefine the lateral boundary condition and give it an initial displacement equal to the ending displacement at the last increment of the previous restart analysis.
I am in search of either some helpful tips on how to successfully complete this analysis procedure, or on a better way to analyze a RC column under psuedo-static cyclic loading. Any help is greatly appreciated!!
Best Regards,
Sam
I have modelled a 3-D reinforced concrete column model in Abaqus. I have used the damaged plasticity concrete model and embedded truss elements for the rebar. My task is to develop a model that estimates the response of an RC column subjected to cyclic lateral loading. I've tried defining an amplitude function for my lateral displacement and running a General Static analysis; however there seems to be too much nonlinearity in the response (even with automatic stabilization) to run. So I took a second stab at the problem. I defined my first input file as a RIKS analysis and pushed the column to a specified lateral dispalcement. I then defined a second input file and restarted the previous analysis. In this retart analysis I defined a second RIKS step and pushed the column from its existing position to its conjugate displacement (0.2" in first input file to -0.2" in second input file). I continue this convention for all displacment cycles defined in my load protocol. I've testing this analysis procedure against experiemental results in the literature and my analytical results predict the behavior very well for low displacement magnitudes. However, I can't get all the way through the load protocol because I run into a problem where the RIKS step starts going in the wrong direction once my displacment magnitude starts to get larger. For instance, lets say I ended the previous RIKS step at a lateral displacement of 0.58". The next restart analysis defines a new RIKS step where I ask it to push the column to -0.58". If I try to do this the analysis gets to about -0.42" then it starts going toward zero again and all the way back up to 0.5". Finally it gives me an error stating that it reached a zero displacement increment and cannot finish the analysis. When I define the restart analysis and define a new RIKS step, I redefine the lateral boundary condition and give it an initial displacement equal to the ending displacement at the last increment of the previous restart analysis.
I am in search of either some helpful tips on how to successfully complete this analysis procedure, or on a better way to analyze a RC column under psuedo-static cyclic loading. Any help is greatly appreciated!!
Best Regards,
Sam