Hi, I am designing an integrated Chair leg with a Weight sensor, The sensor I choose is capable to measure weight up to 150KG that is fine for my purpose, but the impact force can be more then 1 Ton in some cases when a person sit very quickly or jump on the chair. How can I solve this problem? maybe use a different type of sensor?
Add a physical stop for the sensors movement
You can see here an example: http://www.weighingreview.com/2013/06/overload-protection-good-protection-for.html A load cell "reacts" always on "deformation" but in a known range and of cause reversible and without damage. Most load cell tolerate 150% of the maximum load they can measure before breaking. But in your case it make sense to stop the deformation process on a certain point mechanically.
If you don't need great accuracy, repeatability, etc., you might be able to use an FSR. Tekscan's "100 lb model" can take loads up to 1000 lb.