Endurance Limit Modifiers

Описание: Are you an engineer or student designing components for infinite life? The endurance limit (Se)—the maximum stress a material can withstand for theoretically infinite cycles—is a critical design parameter. But the standard endurance limit S’e from laboratory tests is almost always an overestimation for a real-world machine part!
In this video, we dive deep into the essential factors that modify the ideal endurance limit to give you realistic value for your component. We focus on the classic Marin Factors and the famous equation:
Se = ka kb kc kd ke kf S'e
What you will learn in this video:
• Introduction to Fatigue and Endurance Limit: What S'e is and why it needs to be corrected for practical applications.
• Surface Condition Factor (ka): How surface finish (machined, ground, hot-rolled, etc.) dramatically impacts crack initiation and what equations to use.
• Size Factor (kb): The difference between the small lab specimen and your large component—and how the stress gradient is a key player.
• Loading Factor (kc): Why axial, bending, and torsional loading must be accounted for differently.
• Temperature Factor (kd): Designing at extreme temperatures—how high or low heat can alter the material's strength.
• Reliability Factor (ke): Setting your design reliability (e.g., 99% vs. 99.99%) and finding the appropriate safety multiplier.
• Miscellaneous-Effects Factor (kf): A brief look at other crucial effects like residual stresses, corrosion, and plating.