Homework Set 5

Constrained Objects (COBs) and X-Analysis Integration (XAI)

Georgia Tech  CS/ME 6754, COA 8676E  Spring 2001

Due Date: XXX

Reading

This homework set relates to the lectures (a XAI short course) which overview the following slides:

XAI_Technology_Intro_1_COB_Primer.ppt

XAI_Technology_Intro_2_MRA_Primer.ppt

XAI_Technology_Intro_3_Applications.ppt

The following is required reading for this topic area:

1. Introduction to COBs (spring examples):

2001-mit-cfsm-1-wilson-cobs.doc (see related ppt file for the figures)

2. X-Analysis Integration (XAI) Technology

(includes an annotated bibliography)

3. Introduction to the multi-representation architecture (MRA) and its usage of COBs (flap link examples):

2001-mit-cfsm-2-peak-xai-example.doc (see related ppt file for the figures)

The following reading provides further background and applications (see also above annotated bibliography):

4. Towards the Ubiquitization of Engineering Analysis to Support Product Design (IJCAT 1999)

5. Integrating Engineering Design and Analysis Using a Multi-Representation Approach (EWC 1998)

6. An Object-Oriented Internet-based Framework for Chip Package Thermal and Stress Simulation (InterPACK’01)

Problems

Turn in the following (with each item being numbered as shown here for easy reference):

1)20 Points:Given the spring examples from the lecture slides, develop the same type of COB information model structure views (on paper) for a linear resistor model, linear_resistor. I.e., create these views for it:

a)Figure (with labeled parameters)

b)Relations (traditional math form)

c)Constraint schematic-S (schema form)

d)Subsystem view-S

e)Lexical COB structure (COS form – a textual template at the schema level)

f)Constraint graph-S

g)Extended constraint graph-S

Use notation and syntax per the examples in the above slides. Hint: You should define the resistor object template with a voltage point at both ends, such that and .

2)10 Points:Create constraint schematic-I instances (in the solved sub-state) and lexical COB instances (COIs) (in both the unsolved and solved sub-states) showing a linear_resistor instance in the following two states (analogous to the spring instances in the slides).

a)State 1: Use R=5 ohms, V1 = 20 volts and V2 = 10 volts as inputs, with i as the desired output.

b)State 2: Use i=3amps, V1 = 60 volts and V2 = 30 volts as inputs, with R as the desired output.

3)25 Points:Create COB structure information model views (as in Problem 1) for a resistor system (electrical circuit) with three resistors in parallel. This is similar to the building block concepts in the two_spring_system slides. Hint: Remember the linear_resistor primitive already includes several relations. Be careful not to add redundant relations (i.e., derivable relations) at the system level. I.e., only the minimum number of relations needed for system-level boundary conditions should be added (along with relations defining system variables if needed).

a)Figure (with labeled parameters)

b)Relations (traditional math form)

c)Constraint schematic-S (schema form)

d)Subsystem view-S

e)Lexical COB structure (COS form – a textual template at the schema level)

f)Constraint graph-S

g)Extended constraint graph-S

h)Express-G diagram (not included in Problem 1)

i)5 Points - Extra Credit: Create another constraint schematic-S that adds other object(s) to this system in order to determine equivalent overall system resistance without explicitly deriving that relation (see effective spring example).

4)10 Points:Create a constraint schematic instance view (in the solved sub-state) for this resistor system with these inputs: resistor values of 3, 5, and 6 ohms (top to bottom), and Vstart= 60 volts and Vend = 30 volts. The primary desired outputs are the current through each resistor and the total current.

5)25 Points:Implement all the above as in XaiTools FrameWork. Hint: copy and modify the spring examples included in cobs\examples\spring_systems subdirectory. Include the following for Problems 1,2 and Problems 3,4 in your HW documentation:

a)COS model (both the linear_resistor primitive and the resistor system can be defined in the same COS file).

b)COI models in the solved sub-state (one instance per file as saved from XaiTools after solution).

c)Screen capture of the COB Browser with your solved resistor system (Problem 4). Be sure the desired outputs are visible.

XaiTools FrameWork v0.4.2 can be downloaded for class use from here:

The documentation explains how to run the spring examples. It is configured by default to use the CORBA-based Mathematica server in EIS Lab.

Note this version is known to work for Windows NT v4.0, and it may work for Windows 98/ME. The automatic installation does not work for Windows 2000 at present. If you would like to use this tool for research or other usages, please contact Russell Peak.

6)10 Points:Based on the above reading, describe the following concepts briefly in your own words and why they are needed from an information systems perspective (around 5 sentences each): a) ABB, b) SMM, c) APM, and d) PBAM/CBAM.

7)5 Points - Extra Credit:Describe why the following are important for engineering design and analysis: a) ubiquitous analysis, b) ubiquitization (formerly called routinization), c) multi-fidelity idealizations, and d) multi-directionality.

8)5 Points - Extra Credit:Draw a figure like the CAD-CAE “panorama” slides for an example part/assembly of your choice. Include names of several commercial CAD tools and CAE/solution tools, and include at least two behaviors (physical modes) that each have at least two analysis modules (CBAMs) of varying fidelity. For example, let your part be a ball bearing assembly where analysis modules are included for stress and torque behaviors.

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