model Obstacle
  parameter Real c = 1e10;
  parameter Real fixed_x = 0.45;
  input Real x;
  output Real F;
  Real compression;
equation
  compression = x - fixed_x;
  F = if x > fixed_x then c * compression else 0;
  annotation(
    experiment(StartTime = 0, StopTime = 1, Tolerance = 1e-06, Interval = 0.002));
end Obstacle;