FEASTIBILITY STUDY ON THE USE OF PLASTIC COMPONENTS FOR THE 81 MM MORTAR BIPOD ASSEMBLY
PICATINNY ARSENAL DOVER NJ FELTMAN RESEARCH LABS
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Strain data obtained during firing from gages positioned on the legs of the 81 mm mortar bipod assembly was reported to Picatinny Arsenal by Watervliet Arsenal. The forces exerted on the bipod assembly were determined by analyzing this data. Once this was accomplished the individual forces acting upon components could be calculated. A 45 degree elevation was used, with the bipod traverse assembly located in the central position. The calculated maximum stresses were as follows a bearing stress of 20,100 psi on the case and a 2, 780 psi stress due to bending and a compressive stress of 22,880 psi for the tube housing. The cover, body, and yoke ring were not significantly stressed. The connector showed a bending stress of 17,900 psi and a shear stress of 13, 500 psi. Rolled reinforced plastic tubing was suggested for fabrication of prototype components, as it can be easily machined to the desired shapes and has the required strength. It should be noted that the design strength of the tubing is marginal. For end items, a glassfilled epoxy compression molding compound such as Scotchply 1100 would have the desired strength and other required physical properties.