ParaMetric Design - Engineering Design and Analysis - Lecture Slides, Slides of Engineering Drawing and Graphics

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Engineering 11

ParaMetric

Design

OutLine  ParaMetric Design

• Design phase info flow
• Parametric design of a bolt
• Parametric design of belt & pulley
• Systematic parametric design
• Summary

Information Flow

Special Purpose Parts: Features Arrangements Relative dimensions Variable list Standard Parts: Type Variable list

Parametric Design variable values^ Design e.g. Sizes, dimensions Materials Mfg. processes Performance predictions Overall satisfaction Prototype test results

Detail Design Product specifications Production drawings Performance Tests Bills of materials Mfg. specifications

ConFig Design

3x00 Seismic Protection Analysis Plan

• Measure/Calc Weight and Center of Gravity
• Consult S2/§19 for Lateral Loading Criteria (0.63g)
• Consult Mechanical Design Drawing for Seismic Structural- Element Location & Configuration
• Use Newtonian Vector Mechanics to Determine Force & Moment Loads
• Use Solid-Mechanics Analysis to Determine Fastener (Bolt) Stresses
• Use Mechanical-Engineering & Materials Properties to determine Factors of Safety

3x00 S2Testing: Tatsuno Japan, Dec

3x00_S2S8_Tatsuno_PhotoDoc_0112.ppt

3x00 Seismic Loading & Geometry

BMayer

OverTurning Analysis

• Analysis Parameters:
  1. Worst Case → SHORTEST Restoring-Moment Lever-Arm
     • Lever Arms= 582mm, 710mm, 776mm (see slides 4&5)
  2. Vertical (resisting/restoring) Acceleration of 0.85g per SEMI S2 §19.2.
  3. Horizontal (overturning) Acceleration for non-HPM equipment of 0.63g per §19.2.
• Results → Safe From Overturning WithOUT Restraints (but not by much!) Pivot Axis OverTurning Restoring Factor of Line Direction Moment (N-m) Moment (N-m) Safety R-S Y 6884 6966 1. P-Q X 6884 8504 1.

3x00_Seismic_Analysis_0202.xls Docsity.com

Bracket Stress Analysis

• Analysis Parameters
  1. Assume Failure Point at M6 or M10 Bolts
  2. FOUR (4) Angle Brackets With a total of 8 Connecting & Anchor Bolts, Resist Shear
  3. Two Bolts Per Point, Each Bolt Bears 50% of Load
  4. Bolt Axial-PreLoad is negligible (Snug-Fit)
  5. Shear Load Per Restraint Point = 500lb/2.22kN
  6. Use Von Mises Yield Criteria: Ssy = 0.577Sy
• Results

2.22 kN

Bolt Bolt Ssy Load Stress,^ ^ Factor of Size & Fcn Material (MPa) (MPa) Safety M6 Connector SS-304 139.1 13.84 10. M10 Anchor SS-304 139.1 4.74 29. 3x00_Seismic_Analysis_0202.xls Docsity.com

Use Engineering Analysis

• Force Load, F p, That Causes a “Permanent Set” in a specific-sized Bolt is Called the “Proof Load” (N or lbs)
• The “Proof Stress”, S p, is the Proof-Load divided by the supporting Material Area, A (Pa or psi)
• Mathematically the Axial Stress Eqn

S (^) p  Fp A  Fp  ASp

Use Engineering Analysis

• Using ENGR36 Methods Determine the Bolt Load as 4000 lb (4 kip)
• Thus the “Functional Requirement” for the Bolt

Fp  4000 lbs

 To Actually Purchase a Bolt we need to Spec a DIAMETER, d , and a length, L  Find d Using the FR & Stress-Eqn

p

AS (^) p Fp A S

4000 lbs   4000 lbs  

Bolt Grade DEFINES Bolt Size

• Use S p and the FR to find the Bolt Area 2 85000 lb in^2 0047 in

4000 lb A   A .

 Relate A to d using Geometry 4

2 A r^2 d circle

 Since Bolts Have Circular X-Sections

1. 047 in^4 ^0.^047 in ^0. 245 in 4

2 2 2 2 A  d   d   d  



Spec Bolt

• We can PICK any Grade-5 Bolt with a Diameter >0.245” - To Keep down the Bulkiness of the Hardware choose d = ¼” (0.25”)
• Thus We Can Specify the Bolt as
  • Grade-
  • ¼-20 x 6”
    • CHOOSE Coarse Thread (the “20”)
    • CHOOSE a Bolt Length of 6” based on size of Parts Connected

ParaMeterization

• The Bolt Design Problem, After Selecting Grade-5 Material, depends on the Bolt DiaMeter as a PARAMETER
• The Bolt Proof Load as a Fcn of d 2 2

2

2

in

kip 66 8 4 4

d d

d S Fp Sp p  

      

  

  .

^ 

 This ParaMetric Relationship can be displayed in a plot

ParaMetric Design of a Bolted Joint

0

2

4

6

8

10

12

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0. Bold Diameter (in)

Proof Load (Kip)

Bolt_Design_Parametr_d-F_0907.xls

PARAMETERS • Grade-5 Steel

• Sp =85 ksidc NOT Feasible FEASIBLE

Functional Requirement