If those two sentences are the sum total of defining the problem/request, then your Customer wants something with a potentially high chance of useless results!
A small accelerometer can be attached to head of bolt with adhesive stud base or by magnet. Overall acceleration should be measured, since acceleration is proportional to dynamic force. This is the easy part!
The accelerometer can provide a 4-20 ma current output directly or via a transmitter module connected to the control room monitor. The key question is whether the machine monitor/control system can accept (at all, or without disrupting machine operation) the signal for trending and alarming. Modbus connection may also be considered. If these connections are not possible, then you need a different way to handle trending and alarms.
What is the budget and implementation schedule. I will wait for your response before going further with other options.