Modeling and Prototypes

Transcription

1 Modeling and Prototypes Unit 4, Lesson 4 Explanation

2 The Unit Big Idea The Engineering Design process is a systematic, iterative problem solving method which produces solutions to meet human wants and desires.

3 The Lesson Big Idea At various intervals of the engineering design process, conceptual, physical, and mathematical models evaluate the design solution.

4 Modeling There are three different ways to represent our world Written & Spoken Mathematical Graphical

5 Modeling During design process, check for proper design to note areas of needed improvements: Conceptual, physical, and mathematical models evaluate the design solution The usefulness of models can be tested by comparing predictions to observations in the real world

6 Conceptual Models Conceptual models allow designs to quickly be checked and critiqued so that the design may be refined and improved. Technical sketching is a design tool used to create conceptual models

7 Conceptual Models There are several types of technical sketching: Isometric Oblique Perspective Orthographic Technical sketching is a design tool used to create conceptual models

8 Isometric Drawings 3D drawings of objects using true measurements Front & side drawn at a 30 o to horizontal For more info, search for isometric drawing

9 Oblique Drawings 3D drawings with the width represented as a horizontal line. Side view of object drawn at 45 o from horizontal For more info, search for oblique drawing 45

10 Perspective Drawings 3D drawings of objects where lines converge on one or more points. Intended to be close to the human eye in observation. Can converge to 1, 2, or 3 points. For more info, search for perspective drawing

11 Physical Models Can be mock ups or prototypes. Prototype is a working model to test a design concept through observation and adjustment Mock up simulates the look of an object and not functional.

12 Mathematical Models The basic idea of mathematical modeling is to find a mathematical relationship that behaves same way as objects or processes under investigation. Mathematical modeling simulates how a system might behave. Engineers use the language of mathematics to express mathematical ideas precisely.

13 Mathematical Models Engineers create and use representations to organize, record, and communicate ideas. Often symbolic algebra to represent and explain mathematical relationships. Computers have greatly improved the power and use of mathematical models by performing long,complicated,or repetitive calculations.

14 Example of Mathematical Modeling Designer wants to create hot air balloon designs without creating physical models Algebraic formulas represents increases or decreases of lift based on inside volume or temperature Calculations are communicated on spreadsheets or computer based simulations

15 Steps in Creating a Mathematical Model Determine the output you would like to achieve for the mathematical model and what data/information is available Research for other mathematical models already created you can use.

16 Steps in Creating a Mathematical Model Identify relationships among variables (may be related science concepts, such as Ohm s Law) Create the equation that relates variables Check accuracy of model against a similar system or over time.

17 Basic Properties of 2 & 3 Dimensional Objects Engineers and designers must understand basic properties of 2D & 3D objects For 2D objects, one must be able to calculate area For 3D objects, one must be able to calculate volume and surface area These properties help determine modifications related to function and marketability

18 Calculating Area Area is the amount of surface of a 2D object. Formulas are below. Rectangle: A = length x width Triangle: A = base x ½ (height) Circle: A = x radius 2

19 Calculating Volume Volume is amount of space a 3D object takes up. Formulas below. Rectangle Box: V = length x width x height Pyramid: V = Area of Base x 1/3 Perpendicular Height Sphere: V = Diameter 3 x.5236 Cylinder: V = Diameter 2 x Length x.7854

20 Calculating Surface Area Surface area, the measure of how much exposed area a 3D object has. Formulas below Rectangle Box: SA = (H x W x 2) (H x D x 2) (D x W x 2) Pyramid: SA = (Perimeter of Base x ½ Slant Height) + (area of base) Sphere: SA = Diameter 2 x Cylinder: SA= (Diameter x Length of curved surface x ) + (area of bottom + area of top)

21 All Models Important that they function as close to the real world as possible They must be continually checked and refined during the design process. More than one of the three types is often used for the same product