COMPUTER AIDED DESIGN
COMPUTER AIDED DESIGN MECH 403
Popular in Course
Popular in Mechanical Engineering
This 24 page Class Notes was uploaded by Shaina Lowe Jr. on Monday October 19, 2015. The Class Notes belongs to MECH 403 at Rice University taught by John Akin in Fall. Since its upload, it has received 65 views. For similar materials see /class/224973/mech-403-rice-university in Mechanical Engineering at Rice University.
Reviews for COMPUTER AIDED DESIGN
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/19/15
Engineering Optimization Most engineering design involves using optimization software Minimizes or maximizes a merit function Applies functional constraints Applies regional constraints You Must Select or de ne the Merit Function MF the Analysis Variables AV and their subset of Design Variables DV the Analysis Functions AF De ne the constraints Functional Regional Software Tools At least 4 software tools to solve optimization problems of different scope COSMOS nite element stress amp thermal ANSYS nite element multiphysics OPTDESX user de ned TK Solver user de ned Problem Scopes Large FE system with a limited number of prede ned MF AV DV AF MF is a user de ned equation Very general ability de ned by application dependent subroutines in 190 or C OptdesX The XWindows interface to the Optdes Optimum design system Requires 3 userwritten compiled and linked subroutines for AV AF MF Optionally user can supply operating system commands to use a big black box code to form the MF You supply consistent units OptdesX Interface Allows interactive selection mapping of the DV from the AV Allows interactive de nition of the problem constraints Allows interactive de nition of multiple Merit Functions MFs Graphical displays of design history etc OptdesX Algorithms 0 Includes multiple algorithms for Continuous optimization smoothly changing variables Discontinuous optimization tabular non smooth items like pipe sizes or standard structural shapes 3 OptdesX Subroutines ANAPRE ANAlysis PREprocessor is called only once Open les etc ANAFUN ANAlysis FUthions is called every iteration to de ne MF etc ANAPOS ANAlysis POStprocessor is called only if the user hits the post process button Subroutine ANAPRE modelname Provides one time calculations if any before optimization Can also be used to open les needed in ANAPOS or to initialize ANAPRE Often it simply sets the modelName of 17 characters max Subroutine ANAFUN 1 Provides double precision analysis function calculations of the trial vector Three major segments a gets the scalar Analysis Variable AV values from the XWindow subprogram AVDSCA b you must use those AV names to compute needed constants and the Analysis Functions AF values c returns the scalar Analysis Function AF values to the XWindow subprogram AFDSCA Subroutine ANAFUN 2 Step b above could call any other analysis program such as an FE code Optdes provides a operating system level interface to aid With the calls Optdes can run in background These options are dif cult to implement XWindow Interfaces Two arguments to AVDSCA local variable name used in ANAFUN name and units used in the XWindow display limited to 15 characters Two arguments to AVFSCA local variable name you created for the analysis function in step b name and units used in the XWindow display limited to 15 characters Subroutine ANAPOS Provides optional calculations if any after optimization Can be invoked by pushing the quotPost processquot button in the Design Variable Window Usually if this function actually does any calculations they are written to a 10 unit you opened in ANAPRE ANAPRE ANAFUN ANAPOS Fortran 90 source examples are on class web page with compile link and run info C and f77 source examples are in online manual ANAPRE ANAFUN ANAPOS Most common errors Integer division instead of double precision 12 0 not 05d0 as do 1d0 2 or 12d0 Inconsistent engineering units in input and analysis functions Omitting units in XWindow displays OptdesX Documentation PDF Manual is on class web site Continuous optimization tutorial on p 30 Discrete optimization tutorial on p 80 Algorithm theories on p 175 Contents on p 4 Index on p 230 Example source les are on class web site Terminology User Interface Menu Bar gt a m Toolbars Drawing Part document window Status bar Terminology Basic Geometry El Face Ikm The surface or skin Vertex of a part Faces can be flat or curved CI Edge M The boundary of a face Edges can be straight or curved CI Vertex R u The corner where edges meet Terminology Document Window Divided into two FeatureManager design tree 3 panels El Left panel contains the FeatureManager design tree 0 Lists the structure of the part assembly or drawing Graphics Area u El Right panel contains the Graphics Area 0 Location to display create and modify a part assembly or drawing Multiple Views of a Document El Drag the horizontal and vertical split con trols to view 4 panes El Set the view 7 and display options Display Modes SlQQQG39 l B e Illustrate the part in various display modes Wireframe Hidden in Gray Hidden Lines Shaded Removed Document Properties Cl Accessed through the Tools Options menu Document properties control many settings including W CI Units English inches or Metric millimeters CI GridSnap Settings El Colors Material Properties and Image Quality Assembly Basics CI CI An assembly contains two or more parts In an assembly parts are referred to as components Mates are relationships that align and fit components together in an assembly Components and their assembly are directly related through file linking Changes in the components affect the assembly Changes in the assembly affect the components Assembly Basics CI The first component placed into an assembly is fixed CI A fixed component cannot move If you want to move a fixed component autumn you must Float unfix it first El Tutorl is added to the FeatureManager design tree with the symbol f CI The symbol f indicates a fixed component
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'