Created By : Abhinandan Kumar

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 17, 2023


The thermal stress calculator calculates the amount of stress placed on an object due to its thermal load. A change in temperature causes thermal strains. Temperature variations caused by operating, such as engine components or heat exchanger pipes and valves, are thermal loads on a structure. It could also be a temperature fluctuation caused by the weather, such as a significant temperature decrease in cold weather or a hot summer day in the desert.

What is Thermal Stress and Thermal Load on Structure?

Let's look into thermal load before moving on to thermal stress. It is the load placed on a structure as a result of thermal expansion movements. This load is greater in constrained structures that do not allow for any section movement.

Thermal stress is a type of stress that occurs when a load is applied to a structure. To put it another way, the structure expands or contracts as the temperature changes. Mechanical stress, also known as thermal stress, is caused by this movement of the structure. The temperature gradient and the material's expansion rate are also important.

Expansion due to increase in temperature = ΔT = Tf - Ti > 0

Contraction due to decrease in temperature = ΔT = Tf - Ti < 0

You can estimate thermal stress using the thermal stress equation now that you know what it is: σt = E α ΔT

  • Where, σt = Thermal stress
  • E = Young’s Modulus
  • α = Coefficient of thermal expansion
  • ΔT = Change in temperature

What is the Definition of a Temperature Gradient?

It is defined as the temperature change per unit length of a material. It is measured in degrees Fahrenheit (°F), degrees Celsius (°C), or degrees Kelvin (K). The temperature gradient for a sample of unit length is: ΔT = Tf - Ti 

  • Where, Tf = Final temperature
  • Ti = Initial Temperature

What factors have an impact on thermal stress?

The thermal or temperature stress is determined by the following factors:

  • Young's Modulus of the material E;
  • Temperature gradient ΔT;
  •  Linear thermal expansion coefficient.

To determine whether the thermal stress is compressive (-ve) or tensile (+ve), the sign of the temperature gradient is critical. The temperature gradient is positive if the final temperature of the structure is higher than the initial temperature, and vice versa.

How to find out the thermal stress?

To determine thermal stress, use the following formula:

  • Step 1: Determine the material's initial and ultimate temperatures.
  • Step 2: To calculate the temperature difference, subtract the initial temperature from the final temperature.
  • Step 3: Multiply the temperature difference by the thermal expansion coefficient.
  • Step 4: To get the thermal stress, multiply the result by the material's Young's modulus.

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FAQs on Thermal Stress Calculator

1. What is the difference between thermal and thermal stress?

Thermal stress is stress that is created in a body as a result of a change in temperature, and thermal strain is the corresponding strain. When the body's temperature is raised or lowered and the body is not permitted to expand or contract freely, thermal stress occurs.

2. How thermal stresses can affect the body?

Thermal stresses can have a big impact on a structure's strength and stability, leading to cracks and breakdowns in some parts. Such flaws endanger the structure's overall design, perhaps causing it to weaken and deform.

3. What is thermal stress cracking, and how does it happen?

Thermal stress cracks are perpendicular cracks. Sudden temperature changes or changes in the shade of a building might cause this. Impact cracks are cracks that radiate from a centre point in a starburst pattern. An impact crack could happen after hitting a window with a baseball or golf ball.

4. What is the source of thermal stress?

Heat and cold stress are both examples of thermal stress. These circumstances occur when the body's temperature becomes too high for it to handle and compensate for. Cold stress causes the body's temperature to drop, resulting in hypothermia, a potentially life-threatening condition.