Hello,
Though i know that it is not a standard practice in the
space industry to employ conventional free body diagrams for sizing of
fasteners and connectors,I am to size explosive bolts which are used in
the payload fairing separation mechanism using conventional free body
diagrams.
there are two halves with 4 spring actuators in each half these halves attached with a cylindrical barrel(2nd stage in actual) by two hinges.weight,forces in each springs,maximum aerodynamic flight loads(lateral and axial) are known.
how
many bolts and of what size do i need to attach on the lateral and
longitudinal separation planes? do i need to consider both the planes
one by one or as a whole? does the hinge reaction need to be considered ?
the
working philosphy goes: the springs exert an outward rotating moment on
each half about the hinges but the bolts on the longitudinal plane
restrain them from moving apart and likewise the bolts on the lateral
plane restrain the halves from lifting and moving apart.during flight
,considering worst case scenario,we assume that the horizontal
orientation of the fairing is what in which the fairing experiences the
maximum lateral(weight plus aerodynamic flight load) and axial(due to
drag) load.hence the bolts should be sized for this case.
also,is this system a planar or non-planar force system?
explosive
bolts are rated by their tensile load capability but we can see that
during the horizontal orientation the bolts in the lateral plane
experience both tensile and shear loads while the bolts in the
longitudinal plane(when the fairing is on ground ready for launch) only
experience tensile loads due to both halves trying to move apart.
what safety factor is used in space industry for fasteners?
can maximum distortion theory be used to calculate equivalent tensile loads for sizing of explosive bolts?
Free Body Diagram of a Payload Fairing
Re: Free body diagram of a payload fairing
