Bending moments in the tractor-chassis

In a research project "Load spectra for the tractor chassis" (sponsored by Deutsche Forschungsgemeinschaft) the loads on the tractor chassis are investigated. The paper discusses methods for the measurement of bending moments in a tractor chassis. A method is introduced, which works by measuring the external forces and the accelerations, and a following calculation of the bending moments in the chassis. It is shown by experiments that the limited stiffness of the tractor body does not harm the results of the calculation. For varifying the results, the calculated axle loads are compared with the measured ones, the correlation is quite good. Knowing this, it can be stated that it is possible to acquire the axle loads via measuring the external forces and accelerations - without using instrumented wheels. As a first example, results of measurements while subsoil loosening are shown. A recorded time history of the bending moments over the tractor length is shown. For investigations using the random load fatigue theory, a first array of load spectra for the bending moments in the tractor chassis is presented.