# Thermal Stresses in the barrel of a tank

• UsamaHameed
In summary: The barrels are replaced because the thermal stresses they produce increase the chance of a malfunction.

#### UsamaHameed

I want to calculate the thermal stresses in the barrel of a tank. The barrel is smooth bore, auto-frettaged and chrome-platted. I want to know if the thermal stresses are small enough to be neglected and if not, then how can I find them?
Relevant Equation:
Thermal Stress= modulus * coefficient of expansion * change in temperature

Empirically the thermal stresses cannot be neglected. The Muzzle Reference System provides thermal strain input to the fire control computer.

I would like to hear a little more information. Is the barrel constrained in any way? Is it composed of layers of materials with different thermal expansion coefficients?

Chet

The publicly accessible information on the M256 Rheinmetall 120 mm smoothbore gun, the M1 Abrams MBT armament, would suggest not, and it does use a Muzzle Reference System to the FC computer. Remember that the device must be as economical as possible and this one's life span is roughly one ammunition load ~50 rounds.

ETA: Fact checking myself, I noticed that barrel heating by sunlight is specifically mentioned.
ETA II: Over wine at supper I realized that layering might increase hoop strength but not longitudinal strength/stiffness, that would come from an increase in overall diameter/thickness or fluting.

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Wow, just 50 shots?

Yes, with the highest velocity ammo.

Burton, Larry; Robert Carter; Victor Champagne; et al. (1 January 2004). "Army Targets Age Old Problems with New Gun Barrel Technologies". AMPTIAC Quarterly (Rome, New York: Advanced Materials and Processes Technology Information Analysis Center) 8 (4)

Interesting. So in Desert Shield, they were replacing gun barrels like crazy, or did they settle for less accuracy over the few-day campaign?

Even if the barrel is unconstrained and is not layered, thermal stresses can still develop within the barrel as a result of temperature non-uniformities that occur as a result of firing.

Chet

How many rounds were fired and how many on average?

## 1. What are thermal stresses in the barrel of a tank?

Thermal stresses in the barrel of a tank refer to the changes in mechanical stress that occur in the structure of the tank due to temperature fluctuations. As the temperature of the tank changes, its material expands or contracts, leading to internal stresses that can potentially damage the tank.

## 2. How do thermal stresses affect the barrel of a tank?

Thermal stresses can cause the barrel of a tank to deform or even crack if the stress levels become too high. This can compromise the structural integrity of the tank and potentially lead to leaks or other failures.

## 3. What factors contribute to thermal stresses in the barrel of a tank?

The main factors that contribute to thermal stresses in the barrel of a tank include changes in temperature, the material properties of the tank, and the design and construction of the tank itself. Other factors such as external heat sources and environmental conditions can also play a role.

## 4. How can thermal stresses in the barrel of a tank be minimized?

Thermal stresses can be minimized by selecting materials with low coefficients of thermal expansion, designing the tank with proper reinforcements and supports, and implementing insulation to reduce temperature fluctuations. Regular maintenance and monitoring of the tank can also help prevent excessive stress buildup.

## 5. What are the potential consequences of ignoring thermal stresses in the barrel of a tank?

If thermal stresses are ignored, they can lead to significant damage to the tank and potentially result in catastrophic failures. This can not only be a safety hazard but also result in costly repairs or replacements. It is important to properly address and manage thermal stresses in the barrel of a tank to ensure its longevity and functionality.