Adhesion: Bonds and Forces

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Adhesion Bonds and Forces
E3 Teacher Summer Research Program
Texas AM University

• Jose Treviño
• David Leppo

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Motivation

• Why are adhesives important?
• Important part of everyday items and cutting edge
  technology.
• Allows for objects to be bonded without damaging
  them.
• What are some common applications?

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Applications
Flexible Displays
Oil Filters
Oil Filters
Flexible Solar Panels
Coated Containers
Everyday Electronics
Aluminum Siding
Automotive Electronics
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What properties are the focus of project?
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Shear / Tensile Test in the Lab

• Applies Tensile or Shear Stress
• Depends on the orientation of the material

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Simple Adhesive Test for the Class

• How do we test adhesive strengths?
• Measure maximum shear force
• Measure maximum tensile force
• Determine catastrophic failure point
• Presents need for two simple test rigs
• How do we capture attention of students?

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Crazy Scenarios

• Stilt House
• Build house on stilts
• Use adhesives to bond materials
• Flood region impact on adhesive
• Mars Bridge
• Use adhesive to build bridges
• Low supplies on Mars

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Crazy Scenarios

• Adhesive to hold protective foam on space shuttle
• Need strong, non-corrosive adhesive
• Use least amount possible
• How will you test its strength?
• Suspended Underwater Platform
• Buoyancy
• Waterproof adhesive
• Water pressure

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Conceptual Shear Test Rig

• Measure the failure limit of shear forces on
  adhesion.
• Measure the cross sectional area of adhesion.

Load
Adhesion
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Shear Force Test Rig
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Data Collection (Shear)

• Comparing force at failure point and cross
  sectional area.

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Max Shear Force vs Area
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TAKS Objectives Mathematics 9-11

• Obj. 3 The student will demonstrate an
  understanding of linear functions.
• Obj. 8 The student will demonstrate an
  understanding of the concepts and uses of
  measurement and similarity.
• Obj. 10 The student will demonstrate an
  understanding of the mathematical processes and
  tools used in problem solving.

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Conceptual Tensile Test Rig

• Measure the failure limit of tensile forces on
  adhesion.
• Measure the cross sectional area of adhesion.

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Alternative Tensile Test - Magnets

• Use magnets instead of adhesion
• Faster testing
• Cleaner
• Better Results

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Test Rig for Tensile Test (Magnets)
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Data Collection (Normal)

• Comparing force at failure point and cross
  sectional area.

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Max Tensile Force vs. Area
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Force vs Cross-Sectional Area

• Large cross-sectional area means more bonds to
  break.
• The larger the cross-section, the larger the
  force required to cause failure.

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Results

• Bonds should have constant strength regardless of
  cross-sectional area.
• Imperfections and non-uniformities in a material
  can cause deviations in the measured values of
  strength
• What kind of relationship exists between max
  force and area?
• Why is it important to know linear relationships
  exist?

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Cost of Materials
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QUESTIONS