This toolbox allows a rough calculation of safety factors for the different failure types of single-row mechanically fastened joints.
The stress states in loaded and unloaded holes in multi-ply composites are very complex. Despite of the low level of detail of the implemented calculations, it do permit an adequately precise analysis of the load-bearing capacity of pinned joints with frictionless loading since many of the influences ignored here (such as local stress concentrations and the formation of microcracks) work against each other.
In general, pinned joints can transfer high loads in laminates if they are designed appropriately.
This includes an appropriate laminate lay-up with, say,
50 % at 0°,
40% to 45% at +-45° and
5% to 10 % at 90°
to the direction of loading.
The different layers should not be arranged in blocks but rather fine layers and the outer laminae should not be arranged in the 0° direction.
A lateral contact pressure via washers with an adequate surface area will considerably increase the load which can be supported
VDI-Guideline 2014 part 3