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Ice Screws

Author

John Gregel / JJG Engineering Services

Subject

17 cm Ice Screw Placement Angle Analysis Medium Strength Ice

Prepared For

Ice Climbers

Project Created

Monday, December 19, 2005 at 2:06:56 PM

Project Last Modified

Tuesday, January 24, 2006 at 4:02:02 PM

Report Created

Tuesday, January 24, 2006 at 4:12:37 PM

Software Used

ANSYS 10.0

Database

E:\Ansys working\ice screw\Ice Screw analysis.dsdb



1. Summary

This report documents design and analysis information created and maintained using the ANSYS® engineering software program. Each scenario listed below represents one complete engineering simulation.

Scenario 1

Scenario 2

Scenario 3


2. Introduction

The ANSYS CAE (Computer-Aided Engineering) software program was used in conjunction with 3D CAD (Computer-Aided Design) solid geometry to simulate the behavior of mechanical bodies under thermal/structural loading conditions. ANSYS automated FEA (Finite Element Analysis) technologies from ANSYS, Inc. to generate the results listed in this report.

Each scenario presented below represents one complete engineering simulation. The definition of a simulation includes known factors about a design such as material properties per body, contact behavior between bodies (in an assembly), and types and magnitudes of loading conditions. The results of a simulation provide insight into how the bodies may perform and how the design might be improved. Multiple scenarios allow comparison of results given different loading conditions, materials or geometric configurations.

Convergence and alert criteria may be defined for any of the results and can serve as guides for evaluating the quality of calculated results and the acceptability of values in the context of known design requirements.

All values are presented in the "U.S. Customary (in, lbm, lbf, °F, s, V, A)" unit system.

Notice

Do not accept or reject a design based solely on the data presented in this report. Evaluate designs by considering this information in conjunction with experimental test data and the practical experience of design engineers and analysts. A quality approach to engineering design usually mandates physical testing as the final means of validating structural integrity to a measured precision.


3. Scenario 1

3.1. "Screw +15 Deg"

"Screw +15 Deg" obtains geometry from the Autodesk® Mechanical Desktop® assembly "C:\JJG Eng\Desk top projects\Ice Screw\Ice Screw_a+15.dwg".

Table 3.1.1. Bodies
Name Material Nonlinear Material Effects Bounding Box(in) Mass (lbm) Volume (in³) Nodes Elements
"SCREW" "Steel"
Yes
0.88, 2.58, 6.69 0.0 0.85 14801 7304
"HANGER_1" "Steel"
Yes
1.3, 3.35, 0.66 0.0 0.39 2167 962
"ICE_1" "Ice"
Yes
22.0, 22.0, 11.0 0.0 2,732.76 73825 50281

3.1.1. Contact

Table 3.1.1.1. Contact Conditions
Name Type Associated Bodies Scope Normal Stiffness Scope Mode Behavior Update Stiffness Formulation Initial Interface Treatment Offset Thermal Conductance Pinball Region
"Hanger to Screw" Bonded "SCREW" and "HANGER_1" Face, Face Program Controlled Manual Symmetric Never Pure Penalty N/A N/A Program Controlled Program Controlled
"Screw to Ice" Frictionless "SCREW" and "ICE_1" Face, Face Program Controlled Automatic Symmetric Never Pure Penalty Add Offset 0.0 in Program Controlled Program Controlled

3.1.2. Mesh

Table 3.1.2.1. Mesh Sizing Controls
Name Type Element Size Hard Edge Behavior Associated Bodies
"Sizing hanger body" Volume Sizing 0.13 in N/A No Curv/Proximity Refinement "HANGER_1"
"Sizing Screw body" Volume Sizing 0.09 in N/A No Curv/Proximity Refinement "SCREW"
"Sizing Ice Body" Volume Sizing 1.5 in N/A No Curv/Proximity Refinement "ICE_1"
"Sizing Surface screw hole" Face Sizing 0.09 in N/A No Curv/Proximity Refinement "ICE_1"

3.2. "Environment"

Simulation Type is set to Static

Analysis Type is set to Static Structural

"Environment"(Figure A1.4) contains all loading conditions defined for "Screw +15 Deg" in this scenario.

3.2.1. Structural Loading

Table 3.2.1.1. Structural Loads
Name Type Magnitude Vector Reaction Force Reaction Force Vector Reaction Moment Reaction Moment Vector Associated Bodies
"Force" Surface Force 1,800.0 lbf [9.31×10-13 lbf x, -1,738.67 lbf y,465.87 lbf z]
N/A
N/A
N/A
N/A
"HANGER_1"
"Displacement" Surface Displacement 0.0 in [0.0 in x, - y,- z] 5.75×10-2 lbf [-5.75×10-2 lbf x, 0.0 lbf y, 0.0 lbf z] 0.16 lbf·in [0.0 lbf·in x, -0.15 lbf·in y, 4.04×10-2 lbf·in z] "HANGER_1"

3.2.2. Structural Supports

Table 3.2.2.1. Structural Supports
Name Type Reaction Force Reaction Force Vector Reaction Moment Reaction Moment Vector Associated Bodies
"Fixed Support" Fixed Surface 1,800.0 lbf [5.75×10-2 lbf x, 1,738.67 lbf y, -465.87 lbf z] 8,251.53 lbf·in [-8,251.53 lbf·in x, 0.48 lbf·in y, 0.07 lbf·in z] "ICE_1"

Table 3.2.2.2. Weak Springs
Step Reaction Force Magnitude Reaction Force Vector
Step 1 9.39×10-4 lbf [-2.64×10-6 lbf x, 9.38×10-4 lbf y, -3.85×10-5 lbf z]

3.3. "Solution"

Solver Type is set to  Iterative

Weak Springs is set to   Program Controlled

Large Deflection is set to  Off

"Solution" contains the calculated response for "Screw +15 Deg" given loading conditions defined in "Environment".

One or more bodies may be underconstrained and experiencing rigid body motion. Weak springs have been added to attain a solution.

3.3.1. Structural Results

Table 3.3.1.1. Values
Name Figure Scope Orientation Minimum Maximum Minimum Occurs On Maximum Occurs On Alert Criteria
"Equivalent Stress" None All Bodies In "Screw +15 Deg"Global 0.29 psi 90,564.34 psi ICE_1 SCREW None
"Normal Stress" None All Bodies In "Screw +15 Deg"X Axis -32,188.67 psi 31,806.74 psi SCREW SCREW None
"Total Deformation" None All Bodies In "Screw +15 Deg"Global 0.0 in 5.19×10-2 in ICE_1 HANGER_1 None
"Directional Deformation" None All Bodies In "Screw +15 Deg"X Axis -1.23×10-2 in 1.22×10-2 in ICE_1 ICE_1 None
"Equivalent Stress Screw" A1.5 "SCREW"Global 23.01 psi 90,564.34 psi SCREW SCREW None
"Equivalent Stress Ice" A1.6A1.7 "ICE_1"Global 0.29 psi 3,362.38 psi ICE_1 ICE_1 None

Table 3.3.1.2. Solution Information
Table0001.png (512x384 pixels)

Table 3.3.1.3. Solution Information
Table0002.png (512x384 pixels)

4. Scenario 2

4.1. "Screw -0 Deg"

"Screw -0 Deg" obtains geometry from the Autodesk® Mechanical Desktop® assembly "C:\JJG Eng\Desk top projects\Ice Screw\Ice Screw_a.dwg".

Table 4.1.1. Bodies
Name Material Nonlinear Material Effects Bounding Box(in) Mass (lbm) Volume (in³) Nodes Elements
"SCREW" "Steel"
No
0.88, 0.88, 6.69 0.0 0.85 14590 7182
"HANGER_1" "Steel"
No
1.3, 3.35, 0.66 0.0 0.39 2241 1014
"ICE_1" "Ice"
Yes
22.0, 22.0, 11.0 0.0 2,785.09 73705 50213

4.1.1. Contact

Table 4.1.1.1. Contact Conditions
Name Type Associated Bodies Scope Normal Stiffness Scope Mode Behavior Update Stiffness Formulation Initial Interface Treatment Offset Thermal Conductance Pinball Region
"Hanger to Screw" Bonded "SCREW" and "HANGER_1" Face, Face Program Controlled Manual Symmetric Never Pure Penalty N/A N/A Program Controlled Program Controlled
"Screw to Ice" Frictionless "SCREW" and "ICE_1" Face, Face Program Controlled Automatic Symmetric Never Pure Penalty Add Offset 0.0 in Program Controlled Program Controlled

4.1.2. Mesh

Table 4.1.2.1. Mesh Sizing Controls
Name Type Element Size Hard Edge Behavior Associated Bodies
"Sizing hanger body" Volume Sizing 0.13 in N/A No Curv/Proximity Refinement "HANGER_1"
"Sizing Screw body" Volume Sizing 0.09 in N/A No Curv/Proximity Refinement "SCREW"
"Sizing Ice Body" Volume Sizing 1.5 in N/A No Curv/Proximity Refinement "ICE_1"
"Sizing Surface screw hole" Face Sizing 0.09 in N/A No Curv/Proximity Refinement "ICE_1"

4.2. "Environment"

Simulation Type is set to Static

Analysis Type is set to Static Structural

"Environment"(Figure A2.4) contains all loading conditions defined for "Screw -0 Deg" in this scenario.

4.2.1. Structural Loading

Table 4.2.1.1. Structural Loads
Name Type Magnitude Vector Reaction Force Reaction Force Vector Reaction Moment Reaction Moment Vector Associated Bodies
"Force" Surface Force 1,800.0 lbf [9.31×10-13 lbf x, -1,738.67 lbf y,465.87 lbf z]
N/A
N/A
N/A
N/A
"HANGER_1"
"Displacement" Surface Displacement 0.0 in [0.0 in x, - y,- z] 7.06 lbf [-7.06 lbf x, 0.0 lbf y, 0.0 lbf z] 0.75 lbf·in [0.0 lbf·in x, 0.72 lbf·in y, -0.19 lbf·in z] "HANGER_1"

4.2.2. Structural Supports

Table 4.2.2.1. Structural Supports
Name Type Reaction Force Reaction Force Vector Reaction Moment Reaction Moment Vector Associated Bodies
"Fixed Support" Fixed Surface 1,800.01 lbf [7.06 lbf x, 1,738.67 lbf y, -465.87 lbf z] 8,416.63 lbf·in [-8,416.52 lbf·in x, 38.43 lbf·in y, 19.55 lbf·in z] "ICE_1"

Table 4.2.2.2. Weak Springs
Step Reaction Force Magnitude Reaction Force Vector
Step 1 8.92×10-4 lbf [3.62×10-7 lbf x, 8.72×10-4 lbf y, 1.85×10-4 lbf z]

4.3. "Solution"

Solver Type is set to  Iterative

Weak Springs is set to   Program Controlled

Large Deflection is set to  Off

"Solution" contains the calculated response for "Screw -0 Deg" given loading conditions defined in "Environment".

One or more bodies may be underconstrained and experiencing rigid body motion. Weak springs have been added to attain a solution.

4.3.1. Structural Results

Table 4.3.1.1. Values
Name Figure Scope Orientation Minimum Maximum Minimum Occurs On Maximum Occurs On Alert Criteria
"Equivalent Stress" None All Bodies In "Screw -0 Deg"Global 0.2 psi 89,465.14 psi ICE_1 SCREW None
"Normal Stress" None All Bodies In "Screw -0 Deg"X Axis -32,716.67 psi 37,220.38 psi SCREW HANGER_1 None
"Total Deformation" None All Bodies In "Screw -0 Deg"Global 0.0 in 5.66×10-2 in ICE_1 HANGER_1 None
"Directional Deformation" None All Bodies In "Screw -0 Deg"X Axis -8.09×10-3 in 9.09×10-3 in ICE_1 ICE_1 None
"Equivalent Stress Screw" A2.5 "SCREW"Global 28.85 psi 89,465.14 psi SCREW SCREW None
"Equivalent Stress Ice" A2.6A2.7 "ICE_1"Global 0.2 psi 3,363.97 psi ICE_1 ICE_1 None

Table 4.3.1.2. Solution Information
Table0003.png (512x384 pixels)

Table 4.3.1.3. Solution Information
Table0004.png (512x384 pixels)

5. Scenario 3

5.1. "Screw -15 Deg"

"Screw -15 Deg" obtains geometry from the Autodesk® Mechanical Desktop® assembly "C:\JJG Eng\Desk top projects\Ice Screw\Ice Screw_a-15.dwg".

Table 5.1.1. Bodies
Name Material Nonlinear Material Effects Bounding Box(in) Mass (lbm) Volume (in³) Nodes Elements
"SCREW" "Steel"
Yes
0.88, 2.58, 6.69 0.0 0.85 14590 7182
"HANGER_1" "Steel"
Yes
1.3, 3.35, 0.66 0.0 0.39 2185 979
"ICE_1" "Ice"
Yes
22.0, 22.0, 11.0 0.0 2,732.76 73753 50229

5.1.1. Contact

Table 5.1.1.1. Contact Conditions
Name Type Associated Bodies Scope Normal Stiffness Scope Mode Behavior Update Stiffness Formulation Initial Interface Treatment Offset Thermal Conductance Pinball Region
"Hanger to screw" Bonded "SCREW" and "HANGER_1" Face, Face Program Controlled Manual Symmetric Never Pure Penalty N/A N/A Program Controlled Program Controlled
"Screw to Ice" Frictionless "SCREW" and "ICE_1" Face, Face Program Controlled Automatic Symmetric Never Pure Penalty Add Offset 0.0 in Program Controlled Program Controlled

5.1.2. Mesh

Table 5.1.2.1. Mesh Sizing Controls
Name Type Element Size Hard Edge Behavior Associated Bodies
"Sizing hanger body" Volume Sizing 0.13 in N/A No Curv/Proximity Refinement "HANGER_1"
"Sizing Screw body" Volume Sizing 0.09 in N/A No Curv/Proximity Refinement "SCREW"
"Sizing Ice Body" Volume Sizing 1.5 in N/A No Curv/Proximity Refinement "ICE_1"
"Sizing Surface screw hole" Face Sizing 0.09 in N/A No Curv/Proximity Refinement "ICE_1"

5.2. "Environment"

Simulation Type is set to Static

Analysis Type is set to Static Structural

"Environment"(Figure A3.4) contains all loading conditions defined for "Screw -15 Deg" in this scenario.

5.2.1. Structural Loading

Table 5.2.1.1. Structural Loads
Name Type Magnitude Vector Reaction Force Reaction Force Vector Reaction Moment Reaction Moment Vector Associated Bodies
"Force" Surface Force 1,800.0 lbf [9.31×10-13 lbf x, -1,738.67 lbf y,465.87 lbf z]
N/A
N/A
N/A
N/A
"HANGER_1"
"Displacement" Surface Displacement 0.0 in [0.0 in x, - y,- z] 14.9 lbf [-14.9 lbf x, 0.0 lbf y, 0.0 lbf z] 2.13 lbf·in [0.0 lbf·in x, 2.06 lbf·in y, -0.55 lbf·in z] "HANGER_1"

5.2.2. Structural Supports

Table 5.2.2.1. Structural Supports
Name Type Reaction Force Reaction Force Vector Reaction Moment Reaction Moment Vector Associated Bodies
"Fixed Support" Fixed Surface 1,800.06 lbf [14.9 lbf x, 1,738.67 lbf y, -465.87 lbf z] 8,268.37 lbf·in [-8,267.89 lbf·in x, 79.15 lbf·in y, 39.92 lbf·in z] "ICE_1"

Table 5.2.2.2. Weak Springs
Step Reaction Force Magnitude Reaction Force Vector
Step 1 7.11×10-4 lbf [1.27×10-5 lbf x, 6.54×10-4 lbf y, 2.79×10-4 lbf z]

5.3. "Solution"

Solver Type is set to  Iterative

Weak Springs is set to   Program Controlled

Large Deflection is set to  Off

"Solution" contains the calculated response for "Screw -15 Deg" given loading conditions defined in "Environment".

One or more bodies may be underconstrained and experiencing rigid body motion. Weak springs have been added to attain a solution.

5.3.1. Structural Results

Table 5.3.1.1. Values
Name Figure Scope Orientation Minimum Maximum Minimum Occurs On Maximum Occurs On Alert Criteria
"Equivalent Stress" None All Bodies In "Screw -15 Deg"Global 0.2 psi 74,736.45 psi ICE_1 SCREW None
"Normal Stress" None All Bodies In "Screw -15 Deg"X Axis -29,747.5 psi 32,885.0 psi SCREW HANGER_1 None
"Total Deformation" None All Bodies In "Screw -15 Deg"Global 0.0 in 4.98×10-2 in ICE_1 HANGER_1 None
"Directional Deformation" None All Bodies In "Screw -15 Deg"X Axis -7.7×10-3 in 6.84×10-3 in ICE_1 ICE_1 None
"Equivalent Stress Screw" A3.5 "SCREW"Global 116.67 psi 74,736.45 psi SCREW SCREW None
"Equivalent Stress Ice" A3.6A3.7 "ICE_1"Global 0.2 psi 3,804.95 psi ICE_1 ICE_1 None

Table 5.3.1.2. Solution Information
Table0005.png (512x384 pixels)

Table 5.3.1.3. Solution Information
Table0006.png (512x384 pixels)

Appendices

A1. Scenario 1 Figures

Figure A1.1. "Geometry" Geometry
DS0001.png (512x384 pixels)

Figure A1.2. "Mesh" Geometry
DS0002.png (512x384 pixels)

Figure A1.3. "Mesh" Geometry
DS0003.png (512x384 pixels)

Figure A1.4. "Environment" Geometry
DS0004.png (512x384 pixels)

Figure A1.5. "Equivalent Stress Screw" Contours Screw stress @ + 15 Deg
DS0005.png (512x384 pixels)

Figure A1.6. "Equivalent Stress Ice" Contours Ice Stress @ +15 Deg
DS0006.png (512x384 pixels)

Figure A1.7. "Equivalent Stress Ice" Contours
DS0007.png (512x384 pixels)

A2. Scenario 2 Figures

Figure A2.1. "Geometry" Geometry
DS0008.png (512x384 pixels)

Figure A2.2. "Mesh" Geometry
DS0009.png (512x384 pixels)

Figure A2.3. "Mesh" Geometry
DS0010.png (512x384 pixels)

Figure A2.4. "Environment" Geometry
DS0011.png (512x384 pixels)

Figure A2.5. "Equivalent Stress Screw" Contours Screw Stress @ 0 Deg
DS0012.png (512x384 pixels)

Figure A2.6. "Equivalent Stress Ice" Contours Ice Stress @ 0 Deg
DS0013.png (512x384 pixels)

Figure A2.7. "Equivalent Stress Ice" Contours
DS0014.png (512x384 pixels)

A3. Scenario 3 Figures

Figure A3.1. "Geometry" Geometry
DS0015.png (512x384 pixels)

Figure A3.2. "Mesh" Geometry
DS0016.png (512x384 pixels)

Figure A3.3. "Mesh" Geometry
DS0017.png (512x384 pixels)

Figure A3.4. "Environment" Geometry
DS0018.png (512x384 pixels)

Figure A3.5. "Equivalent Stress Screw" Contours Screw Stress @ -15 Deg
DS0019.png (512x384 pixels)

Figure A3.6. "Equivalent Stress Ice" Contours Ice Stress @ -15 Deg
DS0020.png (512x384 pixels)

Figure A3.7. "Equivalent Stress Ice" Contours
DS0021.png (512x384 pixels)

A4. Definition of "Ice"

Table A4.1. "Ice" Constant Properties
Name Value
Poisson's Ratio 0.3
Young's Modulus 435,000.0 psi

Table A4.2. Bilinear Isotropic Hardening
Table0007.png (512x384 pixels)

Table A4.3. "Bilinear Isotropic Hardening"
Yield Strength 1,500.0 psi
Tangent Modulus 10,000.0 psi

A5. Definition of "Steel"

Table A5.1. "Steel" Constant Properties
Name Value
Poisson's Ratio 0.3
Young's Modulus 2.9×107 psi