Shear stress refers to the force per unit area that arises when a material is subjected to a combination of pushing and pulling forces in different directions. For instance, imagine a toy car stuck in between two rocks. When you try to move the car, but it doesn’t move easily because it’s stuck, the force that you apply to the car creates shear stress on the surface of the rocks.
Some examples of shear stress are listed below:
- Walking, where your shoes experience shear stress against the ground
- Stirring, where a spoon experiences shear stress in a liquid
- Sliding furniture on a carpet, where the furniture and the floor experience shear stress
- Rocks in a river, which experience shear stress from the flowing water
- Tightening bolts, where the threads of the bolt and nut experience shear stress
- Cutting paper with scissors, where the blades of the scissors experience shear stress.
The formula for shear stress is:
τ = F / A
where:
- τ is the shear stress;
- F is the force applied perpendicular to the cross-sectional area A of the material.
Table of Contents
Shear stress-Solved Problems
| # | Question | Given Information | Formula Used | Calculation | Shear Stress |
| 1 | What is the shear stress on the wire if you apply a force of 10 N perpendicular to a wire with a cross-sectional area of 0.01 m²? | F = 10 N A = 0.01 m² | τ = F / A | τ = 10 N / 0.01 m² | 1000 Pa |
| 2 | What is the shear stress on a rectangular steel beam that is 2 m long, 0.5 m wide, and 0.1 m thick if you apply a force of 1000 N parallel to the top surface of the beam? | F = 1000 N A = 0.05 m² l = 2 m w = 0.5 m t = 0.1 m | A = 0.05 m² | τ = F / A | 20,000 Pa |
| 3 | What is the shear stress on a cylindrical rod of length 1 m and diameter 0.02 m if you apply a force of 500 N tangentially to the surface of the rod? | F = 500 N d = 0.02 m l = 1 m | A = (πd²) / 4 | τ = F / A | τ = 500 N / (π(0.02 m)² / 4) |
| 4 | What is the shear stress on a metal plate of area 0.1 m² if you apply a force of 5000 N parallel to the surface of the plate? | F = 5000 N | A = 0.1 m² | τ = F / A | τ = 5000 N / 0.1 m² |
Daily Life Examples of Shear Stress
- Brushing your hair: When you brush your hair, the bristles apply a shear force on your hair strands, causing them to slide past each other.
- Spreading butter on toast: When you spread butter on toast, the butter experiences shear stress as it is forced to spread and slide over the surface of the bread.
- Walking: When you walk, the muscles in your legs apply a shear force to your bones, allowing them to move and support your weight.
- Cutting vegetables: When you cut vegetables with a knife, the knife applies a shear force that slices through the vegetables.
- Turning a steering wheel: When you turn a steering wheel, the force you apply to turn the wheel creates a shear stress in the steering mechanism, allowing the wheels to turn and change direction.
How to Measure Shear Stress?
Shear stress can be measured using various methods, including:
- Rheometers, apply controlled stress to a sample of the material and measure the resulting deformation or strain.
- Torsion tests, involve rotating a cylindrical sample of the material and measuring the torque required to maintain a constant rotation rate to calculate the shear stress.
- Parallel plate or cone and plate geometries, involve applying a known force to the sample and measuring the resulting deformation or flow rate to calculate the shear stress.
Different Types of Stress
| Stress Type | Description | Formula | Example |
| Tensile stress | Stress occurs when a material is pushed together or compressed | Tensile stress = Force / Cross-sectional area | Stretching a rubber band |
| Compressive stress | Stress occurs when a material is subjected to opposing forces that are parallel or nearly parallel to each other but act in opposite directions, causing the material to deform in a direction perpendicular to the applied force | Compressive stress = Force / Cross-sectional area | Pressing a spring |
| Shear stress | Stress that occurs when a material is subjected to opposing forces that are parallel or nearly parallel to each other but act in opposite directions, causing the material to deform in a direction perpendicular to the applied force | Shear stress = Force / Area of the sheared face | Cutting a piece of paper with scissors |
Joke about Shear Stress
Why don’t sharks get stressed out at work? Because they’re experts at handling sheer stress!
More Links
Stress in Physics| Definition and Easy Examples
Tensile Stress – Definition, Formula, SI Unit, and FAQs
Compressive Stress – Definition, Formula, SI Unit, and FAQs
How Bulk Stress Affects Materials: Daily Life Examples
Elastic Limit| Definition, Formula, and Simple Explanation
Tension Formula| Daily Life Examples
PhD Student at University College Dublin and Author at What's Insight
PhD Student who loves to write about science, technology and more. Studying at the University College in Dublin. Hope you enjoy my content.
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