Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Physical Property Analysis Introduction to Engineering Design © 2012 Project Lead The Way, Inc. Project Lead The Way® Copyright 2006

Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Physical Properties A physical property is a property that can be observed or measured without changing the identity of the matter. Examples of Physical Properties: Volume Density Color Surface Area Centroid Moment of Inertia Mass Odor Temperature Weight Viscosity Electric Charge Boiling Point Melting Point Attraction to magnets Project Lead The Way® Copyright 2006

Physical Property Analysis Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Physical Property Analysis The size, volume, surface area, and other properties associated with a solid model are often part of the design constraints or solution criteria. The following are physical properties presented in typical solid modeling programs: Volume Density Mass Surface Area Center of Gravity Moment of Inertia Product of Inertia Radii of Gyration Principal Axes Principal Moments Length Project Lead The Way® Copyright 2006

Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Physical Properties We have already investigated density, volume, and mass/ weight Another important physical property is Surface Area Project Lead The Way® Copyright 2006

Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Surface Area Surface area is the area of the exterior surface of an object. Surface area is important when determining coatings and heat transfer of a part. Area A = 3 in. x 4 in. = 12 in.2 Area B = 4 in. x 8 in. = 32 in.2 Area C = 3 in. x 8 in. = 24 in.2 Area D = 4 in. x 8 in. = 32 in.2 Area E = 3 in. x 8 in. = 24 in.2 Area F = 3 in. x 4 in. = 12 in.2 B C D E F A If you consider the flat pattern of the rectangular solid, you can imagine all six sides of the solid. To find the surface area, sum the area of all exterior surfaces of the object. Surface Area = 136 in.2 Project Lead The Way® Copyright 2006

Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Surface Area Another way to represent the formula for surface area of a rectangular prism is given on the formula sheet Project Lead The Way® Copyright 2006

Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Surface Area Surface Area = 2 [(8 in.)(4 in.) + (8 in.)(3 in.) + (4 in.)(3 in.)] = 136 in.2 Project Lead The Way® Copyright 2006

Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Formula Sheet The formula sheet provides formulas for the volume and surface area of many solid forms Project Lead The Way® Copyright 2006

Additional Physical Properties Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Additional Physical Properties Project Lead The Way® Copyright 2006

Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Center of Gravity A 3D point where the total weight of the body may be considered to be concentrated. The average location of an object. If an object rotates when thrown it rotates about its center of gravity. An object can be balance on a sharp point placed directly beneath its center of gravity Project Lead The Way® Copyright 2006

Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Centroid A 3D point defining the geometric center of a solid. Do not confuse centroid with the center of gravity. The two only exist at the same 3D point when the part has uniform geometry and density. Project Lead The Way® Copyright 2006

Mass Property Analysis Principal Axes Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis The lines of intersection created from three mutually perpendicular planes, with the three planes’ point of intersection at the centroid of the part. The X, Y, and Z axes show the principal axes of the ellipsoid. Project Lead The Way® Copyright 2006

Physical Properties and 3D Solid Modeling Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Physical Properties and 3D Solid Modeling Project Lead The Way® Copyright 2006

Physical Properties and 3D Solid Modeling Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Physical Properties and 3D Solid Modeling 3D solid modeling software can display physical properties of modeled objects. In Browser right click on part name Choose iProperties Project Lead The Way® Copyright 2006

Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Physical Properties 3D solid modeling software can display physical properties of modeled objects In Browser right click on part name Choose iProperties Choose Physical tab Choose appropriate material Depress Update button Physical properties are displayed The physical property values will be used to estimate material quantity needed for production and finishing and for estimating packaging and shipping costs. Project Lead The Way® Copyright 2006

Mass Property Analysis Introduction to Engineering Design Unit 3 – Lesson 3.3 – Structural Analysis Sources Brodinski, K. G. (1989). Engineering materials properties and selection. Prentice Hall, Inc.: Englewood Cliffs, NJ. Budinski, K. G. (1992). Engineering materials (4th Ed.). Prentice Hall, Inc.: Englewood Cliffs, NJ. Gere, J. M., & Timoshenko, S. P. (1997). Mechanics of materials. PWS Publishing Company: Boston. Lockhart, S. D., & Johnson, C. M. (1999). Engineering design communication: Conveying design through graphics (Preliminary Ed.). Addison Wesley Longman, Inc.: Reading, MA. Madsen, D. A., Shumaker, T. M., Turpin, J. L., & Stark, C. (1994). Engineering design and drawing (2nd Ed.). Delmar Publishers Inc.: Albany. Project Lead The Way® Copyright 2006