Design ReviewGroup members:

Ed BarnardLizzie HagerJenny Lichter

Kevin McComber

3-11-04

Overview

Goal and Processing Method Ceramic Preform Pressure Vessel Calculations Prototype Mold Design Expected and Threshold Pressures Infiltration ASME Standards for Hammers Methods of Characterization Risks

Halstead

Goal

The goal of our project is to manufacture a light-weight, high fracture toughness hammer using metal matrix composites.

Centrifugal Casting Process

Ceramic Preform

Compression packing May not produce uniform preform Can be improved through agitation

Sintering May form connected ceramic matrix which

could require post processing 3D printing

May be time intensive Binder

Must be able to be burnt out

Numerical Simulations

Monte Carlo Simulations Were considered to model packing density

of ceramic powders Assume spherical particles Our particles are not spherical

Wannasin

Pressure Vessel Calculations

22

22

max .. io

ioUTS

rr

rr

FSP

Pmax = 2200 psi = 150 atm

S. F. : safety factor = 2ri : inner radius = 1.00 inch

Material σUTS (ksi) radiusouter

< σUTS >

radiusouter

(σUTS)min

Brass 30-90 1.08 1.16

Stainless steel 60-150 1.04 1.08

Aluminum 45-80 1.07 1.10

Graphite 7-10 1.77 2.09

Pressure Vessel Calc. Ct’d

Current design: Aluminum 6061

inner radius of 0.75 inches

outer radius of 1.00 inches

Material σUTS (ksi) radiusouter

< σUTS >

radiusouter

(σUTS)min

Aluminum 45-80 0.80 0.82

Prototype Mold

Two-piece mold Conical shape to aid in the release Swagelok connector to runner

5.5

1.0 1.5 3.02.0

1.0

1.75.75

.5

Release from mold

Boron Nitride Spray Coating

Graphite powder

Breakaway ceramic TiC – small particle size Need a binder

Wannasin

Expected Pressures

Moment of inertia calculations Assumption of constant angular energy

I1 ω12 = I2 ω2

2

ω1 = 2200 rpm, ω2 = 1250 rpm

Pressure calculations:

P = ( ½ ) * (ρω2) * (z22 – z1

2)

Currently: 2200 psi or 150 atm

New design: 710 psi or 50 atm

Threshold Pressures

Particulate Size (microns)

Threshold Pressure

(atm)

SiC 7 - 155 2 - 22

Al2O3 5 - 20 8 - 11

B4C 9 3 - 4

TiC 30 5 - 6Based on aluminum infiltration

Generally threshold pressure decreases with increasing particle size

Infiltration

Larger particles necessary Previously used particles a few microns in

size Future Particles (already purchased)

Boron Carbide 100 grit (106-150 microns) Silicon Carbide 120 grit (90-125 microns) Silicon Carbide 36 grit (600-850 microns)

Halstead

Safety Requirements (ASME):Design Parameters

Chamfer striking face 45 degrees with length equal to 1/10 of bell (to prevent chipping)

Striking face must be flat or convex

No unnecessary sharp edges, points or surface roughness

Striking FaceChamfer

Bell

Safety Requirements (ASME):

Mechanical Properties

Hardness Test Striking face hardness: 40-60 HRC Hardness must be maintained at least .75

in. into bell

Striking Test Average person (160-180 lbs) must strike

steel (of hardness 92-105 HRB) 20 times without causing damage

Safety Requirements (ASME):

Mechanical Properties Cont.

Assembled Parts Tests (calculated for hammerhead of 300-350 grams)

Static Test 556 Newtons or 125 lbs.

Tensile Test (for non-wedged assemblies) 3340 Newtons or 750 lbs.

Methods of Characterization

SEM Estimate ceramic volume fraction Possible defects – microvoid formation Incomplete infiltration

Rockwell Hardness Impact tests Tensile and compression tests

Plastic deformation

Risks

Particle size leads to incomplete infiltration Reduce mold weight Increase particle size Different preform production method

Mold leaks O-ring system Use outer tube to hold molds

Risks, Ct’d

Part cannot be removed Use stronger mold release spray Change angle of mold

Low hardness Choose different ceramic particles with

better wettability with respect to metal Use multiple types of ceramic particles

Air pockets Design an evacuation system

Projected Work Schedule

2/5 2/12 2/19 2/26 3/4 3/11 3/18 3/25 4/1 4/8 4/15 4/22 4/29 5/6 5/13Materials

Metal choiceCeramics choice

Part productionCADAlum. machined mold

Ceramic preform

Volume fraction Time PermittingSize distribution "

Final testing

CODE:Task Sub-task Gradation Testing

Works Cited

Halstead, Gary. “Pictures from Dictionaire Paisonné du Mobilier Français.” Accessed 24

February 2004. Medieval and Renaissance Woodworking. 2003.

<http://www.medievalwoodworking.com/vld_tools.htm >.

Wannasin, Jessada. PhD Thesis. March 2004.