The first step in designing or analyzing any structure is to understand “right” set of loads. Typically, off-road vehicles have many access doors for service or getting into cab etc. Design of these doors and their latches involve a knowledge of the loads arising when the door is shut which usually involves an impact of varying magnitudes.
In scenarios of these impact events, where there is sudden change of velocity within few milliseconds, produces high magnitude of loads on structures. One common way of estimating these loads using hand calculations involves evaluating the rate-of-change-of-momentum. However, this calculation needs “duration of impact”, and it is seldom known/difficult to estimate. Failing to capture duration of impact event will change load magnitudes drastically, e.g. load gets doubled if time-of-impact gets reduced from 0.2 to 0.1 seconds and subsequently fatigue life of the components in “Door-closing-event” gets reduce by ~7 times.
For these problems, structures are usually designed and analyzed with certain assumptions for impact loads, and they end up overdesigned or under designed for the reasons cited above. To design doors/latches structures under these impact loads further gets challenging due to not-so-easy way of measurements of impact forces.
In this presentation, authors talk about how door closing/latching impact loads were developed using frugal use of pedal force sensor. To validate the impact forces recorded by pedal force sensor, traditional strain gauges and effective use of mathematical technique of load reconstruction was employed. Authors validate the use of pedal force sensor as an impact force measurement device.