Evaluation of Fatigue Damage and Life Estimation Using SOLIDWORKS Simulation  

Understanding Fatigue and Durability  

Durability, often assessed through fatigue analysis, is the ability of a component to withstand repeated loading over time. In real engineering applications, failures rarely occur due to a single overload; instead, they result from cyclic stresses that accumulate damage progressively.

Repeated loading and unloading can weaken components even when the induced stresses are well below allowable limits. This phenomenon, known as fatigue, is one of the most common causes of mechanical failure.

Each stress cycle contributes a small amount of damage. While individual cycles may appear insignificant, their cumulative effect leads to material degradation. After a sufficient number of cycles, the component becomes critically weakened and ultimately fails.

Fatigue is a primary failure mechanism in many engineering systems, particularly in metallic components. Typical examples include:

• Rotating machinery

• Bolts and fasteners

• Aircraft wings

• Automotive axles

• Bridges and offshore structures

• Consumer products

• Biological structures such as bones

Stages of Failure Due to Fatigue:

Fatigue failure develops progressively under cyclic loading. It is typically described in three stages, each with distinct physical behaviour and design implications.

Stage 1: Crack Initiation  

The first stage begins with the formation of small cracks, typically in areas exposed to repeated stress, surface imperfections or geometric stress concentrations.

Stage 2: Crack Propagation  

With continued cyclic loading, the initiated crack gradually grows. The rate of crack propagation depends on factors such as stress levels, material properties and loading conditions.

Stage 3: Final Failure (Fracture)  

Once the crack reaches a critical size, the remaining cross-section of the component can no longer withstand the applied load, resulting in final fracture.

Preparing the Model for Fatigue Analysis  

Before performing fatigue analysis, a linear static simulation is first carried out. It uses stress results obtained from a reference structural study.

For this study, we are simulating a situation where:

• The backboard side is fully constrained.

• The rim is pulled downward at a specific location.

This setup helps us understand how the structure behaves under realistic conditions, including how it bends, where stress develops and which areas are critical.

The biggest advantage of SOLIDWORKS Simulation is that design and simulation work together in a single environment. Design changes can be reflected in the analysis, making it easier to evaluate and refine the model throughout the development process.

Fatigue Analysis of the Basketball Rim  

While the static study shows how the rim behaves under a single high load, real-world usage involves repeated loading during gameplay. Every shot, dunk and impact applies cyclic stresses to the structure. To evaluate long-term durability, a fatigue analysis is performed based on the stresses obtained from the static study.

The objective of this study is to estimate the life of the rim under repeated loading conditions and identify regions prone to fatigue failure.

The basketball rim is fixed at the mounting plate, representing its attachment to the backboard. A downward load of 1000 N is applied on the rim to simulate real-world conditions such as a player performing a slam dunk.

The stress and displacement results obtained from the analysis are presented below:

While the static nonlinear study shows how the rim behaves under a single high load, real-world usage involves repeated loading during gameplay. Every shot, dunk and impact applies cyclic stresses to the structure. To evaluate long-term durability a fatigue analysis is performed based on the stresses obtained from the static study.

Fatigue analysis:

The objective of this study is to estimate the life of the rim under repeated loading conditions and identify regions prone to fatigue failure.

Types of Fatigue Studies  

SOLIDWORKS Simulation supports different types of fatigue studies for evaluating component durability under different loading conditions:

• Constant amplitude event study

• Variable amplitude event study

• Harmonic fatigue of sinusoidal loading

• Random vibration fatigue

The appropriate study type depends on the nature of the loading experienced by the component.

Applying the S-N Curve  

To run a fatigue study, an S-N curve must be assigned to the material used in the model. This curve defines the relationship between alternating stress and the number of cycles a material can withstand before fatigue failure.

The curve can be created by entering alternating stress versus number-of-cycles data or by selecting an existing S-N curve from the material database.

For this study, the appropriate S-N curve is selected from the material database and applied to the model.

After material properties the most important step is to add loading events:

The below figure shows the definition of a constant amplitude fatigue event in SOLIDWORKS Simulation. The fatigue life is evaluated over 10,000 load cycles, using a zero‑based load ratio (R = 0) where the load varies from zero to the maximum value obtained from the associated rim static study.

Result Interpretation:

Above plot shows the fatigue damage percentage in the component after cyclic loading. The colour scale represents how much of the fatigue life is consumed at each location.

The highlighted region shows a maximum damage of 48.2%, meaning nearly half of the fatigue life is already used under the defined loading conditions. Blue areas indicate minimal damage, while warmer colours pinpoint fatigue‑critical zones caused by higher stress concentrations.

the part is safe for now but this region is the first to fail if loading continues.

Above plot shows the predicted fatigue life in cycles obtained from SOLIDWORKS fatigue analysis. The minimum life of approximately 20766 cycles identifies the most critical location, which governs the overall durability of the component.

 Evaluating Fatigue Damage   

The fatigue damage plot shows the percentage of fatigue life consumed by the component after cyclic loading. The colour scale represents how much of the fatigue life has been used at each location.

The highlighted region shows a maximum damage of 48.2%, meaning nearly half of the fatigue life has already been consumed under the defined loading conditions. Blue areas indicate minimal damage, while warmer colours identify fatigue-critical zones caused by higher stress concentrations.

The part is safe under the defined conditions for now, but the highlighted region represents the location most likely to experience fatigue failure first if the loading continues.

Predicted Fatigue Life  

The predicted fatigue life shows the number of cycles the component can withstand under the defined loading conditions. SOLIDWORKS Simulation Software predicts a minimum life of approximately 20,766 cycles at the most critical location.

This minimum-life region governs the overall durability of the component and provides engineers with a clear indication of where fatigue performance may need to be improved.

SOLIDWORKS FEA Analysis for Fatigue Evaluation  

The fatigue study builds on the results obtained from the structural analysis. SOLIDWORKS FEA Analysis helps engineers understand stress distribution and identify critical regions before using those results for fatigue-life estimation.

By combining finite element analysis with material fatigue data and realistic loading conditions, engineers can evaluate both the immediate structural response of a component and its expected performance under repeated loading.

Conclusion  

Fatigue analysis goes beyond checking whether a part is strong enough; it answers the more important question of how long the part will last under real operating conditions. By combining linear static results, material S-N curves and realistic loading events, engineers can predict fatigue life, identify critical regions and reduce the risk of unexpected failure.

SOLIDWORKS Simulation Software bridges the gap between structural analysis and real-world durability by converting stress results into meaningful fatigue-life information. This helps engineers make informed design decisions and develop safer, more reliable and longer-lasting components.

Created By: Abhijeet Abhimanyu Shedage

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