Sia27
Civil/Environmental
- Jan 8, 2015
- 5
Hi,
I thank you in advance for any advice I can get.
I am modeling contact between 3 steel surfaces in Abaqus. The three surfaces are connected by screw at intermittent spacing in the longitudinal direction. I used contact pair, surface-to-surface contact where I assigned the middle steel as double-sided master surface and the right and left steel as slave surfaces. For the middle double-sided master surface, I specify the normal at the SPOS surface towards the slave surface at the right side (forming Contact 1) and the normal at SNEG surface towards the slave surface at the left side (forming Contact 2). The normal direction of both right and left slave surfaces are towards the master surface in the middle.
Small sliding is used. Because this is metal, I used "hard" pressure-overclosure and direct contact constraint enforcement method. I applied this through the "normal behaviour" in abaqus. Basically, under the applied load, the three surfaces are expected to separate to some extent in the area between the screw but the screws are not separating and will not fail. In a way, tangential sliding is minimal.
My question is, I am not sure if I am supposed to be applying coeficient of friction in the contact pair. I carried out elastic buckling analysis for the same model but at different screw spacing (i.e. Model 1: 25 mm spacing throughout the length , Model 2: 100 mm spacing throughout, Model 3: 300 mm spacing etc). When I assigned 0.4 coefficient of friction, the elastic buckling moments reduces as screw spacing increases. However, when I assigned 0 coefficient of friction, the opposite happens: the elastic buckling moments increases as screw spacing increases. However the consistent finding with both 0 and 0.4 coefficient of friction is the ultimate moment from nonlinear analysis reduces with increasing screw spacing (this is of course expected).
Once again, many thanks.
I thank you in advance for any advice I can get.
I am modeling contact between 3 steel surfaces in Abaqus. The three surfaces are connected by screw at intermittent spacing in the longitudinal direction. I used contact pair, surface-to-surface contact where I assigned the middle steel as double-sided master surface and the right and left steel as slave surfaces. For the middle double-sided master surface, I specify the normal at the SPOS surface towards the slave surface at the right side (forming Contact 1) and the normal at SNEG surface towards the slave surface at the left side (forming Contact 2). The normal direction of both right and left slave surfaces are towards the master surface in the middle.
Small sliding is used. Because this is metal, I used "hard" pressure-overclosure and direct contact constraint enforcement method. I applied this through the "normal behaviour" in abaqus. Basically, under the applied load, the three surfaces are expected to separate to some extent in the area between the screw but the screws are not separating and will not fail. In a way, tangential sliding is minimal.
My question is, I am not sure if I am supposed to be applying coeficient of friction in the contact pair. I carried out elastic buckling analysis for the same model but at different screw spacing (i.e. Model 1: 25 mm spacing throughout the length , Model 2: 100 mm spacing throughout, Model 3: 300 mm spacing etc). When I assigned 0.4 coefficient of friction, the elastic buckling moments reduces as screw spacing increases. However, when I assigned 0 coefficient of friction, the opposite happens: the elastic buckling moments increases as screw spacing increases. However the consistent finding with both 0 and 0.4 coefficient of friction is the ultimate moment from nonlinear analysis reduces with increasing screw spacing (this is of course expected).
Once again, many thanks.