Downloaded from https://www.everyspec.com APPENDIX C MIL-STD-31000A C.7.2.3. Non-smooth surfaces or patches (G 2 discontinuity) (G-SU-NS). Definition: Radius of curvature changes abruptly in magnitude at the common boundary of two surfaces or patches. Measurement: ratio of the difference in radius of curvature over mean radius, |r1-r2|/(r1+r2)/2 Discontinuous curvature is a quality defect only if adjacent surfaces are required by designers to have continuous curvature. Design or drafting: A quality defect only when curvature continuity is required. Data exchange: No harmful effects on data exchange. Finite-element analysis: No harmful effects on mesh generation or model solution.
Numerically controlled manufacturing: Curvature discontinuity is visible in finished parts. No effect on machining operations. Recommended correction: Adjust one or both surfaces to eliminate the unwanted condition. C.7.2.4. Tiny surface or patch (G-SU-TI). Definition: Area of surface or patch is below permissible minimum. Effects of condition on CAD data quality: Design or drafting: Cross sectional views, fillets, rounds, and offset surfaces may fail. Slight increase in model storage requirements due to unnecessary entities. Data exchange: Faces may not trim properly. Finite element analysis: Unwanted mesh elements may be produced. Automatic mesh generation may fail.
Numerically controlled manufacturing: May slow operations. Tool-path generation may fail. 93