Tools › Mechanical Design › Mass Properties

Mass Properties

1 tool in the Mechanical Design area.

Mass Properties from BOM

Mass, centre of gravity and inertia tensor of an assembly from its bill of materials: each row is a part with a quantity, a shape (point mass, box, solid cylinder, tube, solid sphere, hollow sphere, plate or an entered tensor), its mass or its density with the dimensions, the direction of its long axis and the position of its centroid in the assembly frame. Each part's inertia tensor about its own centroid comes from the closed forms of the handbook tables, is rotated to the chosen axis and moved to the assembly centre of gravity by the parallel-axis theorem; the page reports the total mass, the centre of gravity, the tensor about the centre of gravity and about the frame origin, the principal moments and axes from a Jacobi eigen-solve, the radii of gyration, each part's share of the mass and of the three moments, the sensitivity of the centre of gravity to each part, an optional mass-uncertainty bound by root-sum-square, and a two-view drawing of the parts with the centre of gravity marked. Masses, lengths, densities and moments of inertia go through the unit selector (lb, in, lb/in³, lb·in² or kg, mm, kg/m³, kg·m²). The default is a five-part assembly with round numbers, a base plate, a housing given by its density, two cylinders and a pair of connectors as point masses, which the test script checks against the closed forms, the parallel-axis theorem and an independent numpy evaluation.

Other Mechanical Design sections

Shafts · Gears · Bearings · Springs · Fasteners and Power Screws · Pressure Vessels · Tolerances · Vibration · Acoustics · Brakes, Clutches and Belts · Machining and Manufacturing · Lubrication and Wear