Hello all, i'm trying to analyse the vertical deflection of a beam traversed by a point load as shown in the figure. The load has the following format: F=Pcos( ωt+ϕ) where P is the load amplitude (N), ω is the radial frequency of the applied load (rad/sec), V is the speed of the moving load (m/s) and t is the time (s). ϕ is an initial phase applied to the load to ensure that for every frequency, it will arrive at the mid-span with maximum amplitude. Please guide me, how would I define that in Ansys workbench?
Thank you.
Hajar Rhylane
Take a look:
1. https://www.researchgate.net/post/How_can_i_create_a_moving_harmonic_load_in_ANSYS_workbench
2. https://www.youtube.com/watch?v=_1BASk_VyCQ
I agree with Claudio Pedrazzi
Sir. You will have to run a transient structural analysis and use APDL programming to simulate the moving load. Assuming constant moving load speed and taking the load to be at the leftmost end of the beam at time t = 0, we may proceed as follows
Hi @Hajar Rhylane.
I would like to add a method to do this without programming using Ansys Workbench.
You may resort to solid modeling of the beam and create a body that has contact with the solid beam. The contact between the body and the solid beam should be only at one location along length at any point of time. The contact surface should be the solid beam surface and the target should be the edge of the body in contact with the solid beam. The acceleration can be applied on the body and should be adjusted to match the required contact force that has to be applied to the solid beam by contact. Hence the acceleration can be defined by a function something like a.cos(wt+phi). The type of contact can be defined as no separation contact. The linear velocity v cab be applied to the body directly.
However it has to be noted that the linear velocity v and the angular velocity w are not independent and cannot be defined arbitrarily because of the requirement that it has to arrive at the centre with the maximum amplitude. The relation between v and w can be determined by solving the two equations 1) wt1+phi = n.pi and 2) vt1= L/2. Where t1 is the time at which the body reaches the mid length of the beam. The parameter t1 can be eliminated to get the relation between w and v. The parameter n can take any whole number value.
And please remember to switch on finite sliding in the contact settings. Hope this helps.
In ANSYS Workbench, the simulation can be done as mentioned by Mir Aamir Abbas Sir. Just wanted to point out the fact that the original problem as stated in the question is known as the moving force/load problem where one has a structure (beam in this case) that is subjected to an external moving force. Thus, one has to solve the governing partial differential equations (PDEs) of the structure to obtain the response of the structure.
The suggestion given by Mir Aamir Abbas Sir is known as the moving mass problem. Here, one has the structure (beam) on which an external body is moving. Thus, it is necessary to simultaneously solve the governing equations for both the structure and the moving body to obtain the response of the structure and the moving body. This is much more involved than the moving force problem but reflects the real-life scenarios accurately.
Also, it is necessary to specify whether the moving body is rigid or deformable. If it is rigid, then its motion will be governed by ordinary differential equations while that of the structure will be governed by PDEs. If it is deformable, then both the moving body and the structure will be governed by PDEs.
In addition to the moving force and moving mass problem, another case is a moving spring-mass-damper problem which is used to study the effect of suspension properties of moving vehicles on the vibration of bridges. The following paper can be referred to for more information on the same.
T. Dahlberg, Vehicle-bridge interaction, Vehicle Syst. Dyn. 13 (1984) 187–206
Thank you very much for your answers and for your interest in my question and I apologize for the late response. If it's possible to do this on ANSYS Workbench, can you show me please how to do it. Thank you once again.
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