Downloaded from https://www.everyspec.com APPENDIX C MIL-STD-31000A C.7 EXHIBIT A – PRODUCT GEOMETRIC INTEGRITY CRITERIA. C.7.1. Geometry. C.7.1.1. Curve criteria Large segment gap (G 0 discontinuity) (G-CU-LG). Definition: The distance between end points of adjacent curve or line segments is excessive. Curves may be separated by a gap or may overlap. Measurement: gap width or overlap in mm Effects of condition on CAD data quality: Design or drafting: When curves are offset, gaps between segments may be enlarged or overlapping segments may intersect. Cross-sectional views may fail. Data exchange: Faces associated with curves may not trim properly. Finite element analysis:
Unwanted mesh elements may be produced. Automatic mesh generation may fail. Numerically controlled manufacturing: Gouges or abrupt changes in angle may occur when cutting curve surfaces. Recommended correction: Limit the distance between end points to less than the recommended values. The preferred correction method is extending or trimming one or both entities. C.7.1.2. Non-tangent curves or segments (G 1 discontinuity) (G-CU-NT). Definition: Tangent angle changes at the common endpoint of adjacent curves, Δθ (≤ 90°). Measurement: difference in tangent angle of two curves at common end point, Δθ 84