Knee sounds like it's ripping when I bend it?

Crepitus. Sounds coming from a knee when it bends could be crepitus which are rubbing of the bones in arthritis. An xray and evaluation is needed.
Have it evaluated. Sound coming from the knee could be due to tendon, cartilage, meniscus, or bone abnormalities. Have it evaluated by your orthopedist and find out why it is making that sound.