{"id":367434,"date":"2024-05-18T10:00:28","date_gmt":"2024-05-18T10:00:28","guid":{"rendered":"\/forum\/forums\/topic\/tennis-ballhyperplastic-hitting-strings\/"},"modified":"2024-05-18T10:00:28","modified_gmt":"2024-05-18T10:00:28","slug":"tennis-ballhyperplastic-hitting-strings","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/tennis-ballhyperplastic-hitting-strings\/","title":{"rendered":"Tennis Ball(hyperplastic) hitting strings"},"content":{"rendered":"
Hello.<\/div>\n
The project involves impacting a tennis ball (made from hyperplastic rubber with internal pressure) against pre-tensioned tennis strings (made from polyester and nylon) at a maximum velocity of 265 km\/h in a direction normal to the string bed. Observing the stress and deformation, the objective is to determine the thinnest possible string for the two materials under test.<\/div>\n
 <\/div>\n
I thought of conducting multiple steps from simple to more complicated toward the main project: <\/div>\n
 <\/div>\n
1-Testing the solid ball(with Ansys predefined Explicit>Rubber-2 material) against a rigid plate : <\/div>\n
 <\/div>\n
-body interaction: proximity-based frictionless<\/div>\n
<\/div>\n
-mesh<\/div>\n
 <\/div>\n
 <\/div>\n
-ball velocity: 7m\/s<\/div>\n
-plate displacements=0<\/div>\n
 <\/div>\n
-analysis setting: <\/div>\n
end time: 2e-2<\/div>\n
automatic mass scaling=no<\/div>\n
max no of cycles: 1e7<\/div>\n
 <\/div>\n
RESULT:<\/div>\n
The ball bounced back when hitting the plate<\/div>\n
  <\/div>\n
 <\/div>\n
Issue 1: when we increase the speed(50m\/s), some ball elements penetrate and get stuck into the plate, preventing the ball from rebounding. we tried refining the mesh but the issue insisted.<\/div>\n
<\/div>\n
 <\/div>\n
issue 2: we acquire the tennis ball and polyester string material properties(stress-strain curve) but assigning it to them gives us an error.<\/div>\n
 <\/div>\n
  <\/div>\n
 <\/div>\n
 <\/div>\n
error: <\/div>\n
“You have specified result time(or frequency) = 0.00226447262556333 for a result file which has maximum time(or frequency) = 4.19585521740373e-05.  If you specify 0(ZERO), the solution for the final time will be displayed.”<\/p>\n<\/div>\n
issue 3: Regarding applying a pretension force on the string in the main analysis, we have difficulty effectively applying it.<\/div>\n
 <\/div>\n
I attached the verification(Ball_impacting_plate), the main project file and the materials stress-strain data. Materials are also already added to the Engineering Data of the verification file.<\/div>\n
Main Project<\/a><\/div>\n
Ball Plate<\/a><\/div>\n
polyester stress-strain curve<\/a><\/div>\n
Rubber Stress-strain curve<\/a><\/div>\n
 <\/div>\n
I appreciate your help.<\/div>\n
Thank you<\/div>\n","protected":false},"template":"","class_list":["post-367434","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t