Why is my 3D printer not extruding properly?
Underextrusion and clogs can also be caused by insufficient temperature in the hot end. You've not reference your temperatures, so consider to use a test model and print at different temperatures. Too low temps can result in the problem you present, while too hot temps will increase stringing and peculiar blobs on the print. 

If your slicer changes print speed at the layer of destruction, it may also be too fast, which is related to temperatures. Simplify3D allows speed variation as well as temperature variation at selected layers, but it requires deliberate action on the part of the operator.