The ability to determine allowable stresses in compression springs is crucial for practical spring design and selection. It involves defining an appropriate balance between the stress resistance needed and the specifics design parameters of the spring for its smooth operation when loaded and unloaded. As an illustration, if we are designing a compression spring for an industrial conveyor, considering the stress allowance during the design phase can fend off unexpected interruptions due to spring failure. On the other hand, a spring for a device used less often may not need the same stress resistance as that for heavy-duty machinery. The decision on allowable stress is therefore influenced by the unique context and plays a role in enhancing the performance and quality of the final product.

Understanding Compression Springs and Stresses

Compression springs are a specific type of springs that react to force applied along their axis. They have wide-ranging applications due to their ability to resist and respond to force. For example, they are included in devices such as retractable pens and car suspensions.

Considering a car's suspension system, we can better understand the role of compression springs. If a car encounters a bump, the spring compresses, absorbing the resultant shock. This reaction mitigates the shock's impact, improving the ride. When the load decreases, the spring returns to its original length.

In the operation of springs, the concept of stress plays a major role, which denotes the internal force per unit area exerted by a spring when it deforms. This deformation can be due to external forces or changes in external conditions like temperature, resulting in bending or compressive stress. Accurate calculation of this stress is necessary to validate that the springs can withstand the expected load conditions.

Exploring further the practical consequences of stress calculation, let's again consider the car suspension system. If the actual stresses on the spring during maximum load conditions exceed the allowable stress limits, the spring is liable to premature failure. This condition can potentially affect the car's stability. However, an accurate calculation of these forces allows the engineers to design a spring with an appropriate stress threshold, consequently prolonging the car's suspension system's lifespan and improving safety.

Characteristics Influencing Spring Stress Resistance

Calculating Allowable Stresses- Steps and Formulae

Balance Between Spring Design and Stress Calculation

The procedure to design useful compression springs and evaluate their stress upper bounds requires comprehending changing factors. These factors include the selected material's characteristics, the diameter of the wire, the spring index, environment conditions, and the function of the spring.

As an example, the selection of material can change a spring's behaviour under stress. A spring made from music wire, recognized for its substantial carbon content, has typically better stress absorption capabilities than a spring made from stainless steel. Hence, the material selection should bear consideration in the engineer's design process.

The diameter of the wire and the spring index values can affect a spring's stress levels. Smaller wire diameter or a larger spring index could potentially enhance the stress experienced by a compression spring. However, this relationship might not always be valid due to the influence of varying factors like material properties.

In conclusion, the working environment of the spring, including temperature variations, and the spring's purpose, can impact its stress tolerance. For example, a compression spring in use in a car engine, subjected to a high-temperature environment, may display diminished elasticity and therefore necessitate a design with reduced stress tolerance. Grasping such considerations aids engineers in designing springs that meet necessary performance measures safely.


Determining the exact allowable stresses in compression springs is crucial for your design process, helping to avert unwanted issues and ensure reliability in your application. It requires a clear understanding of how springs work, especially the stresses they are subjected to, and taking into account the properties that influence stress resistance. Thus, knowing how to compute allowable stresses in compression springs is a crucial step in engineering design.