The forced entry of structures or locks subjects tools to extreme load cycles and plastic deformation. This article analyzes, through 3D numerical simulation, the fatigue process that leads to the failure of tools such as crowbars and punches. Accumulated Von Mises stresses and stress concentration zones are studied to predict breakage points.
Analysis of residual stresses and accumulated deformation 🔧
In the simulation, we modeled the geometry of a carbon steel crowbar subjected to 5000 load cycles with a peak of 1200 N. The results show an accumulation of plastic deformation at the notch radius, reaching 0.8% equivalent strain. Heat map visualization reveals that low-cycle fatigue (LCF) is the dominant mechanism. When compared to a heat-treated (case-hardened) steel model, the service life is extended by 40% due to reduced nucleation of surface microcracks.
Material optimization for durability in service ⚙️
The key insight is that the design must withstand not only the maximum load but also the accumulation of damage. 3D simulation allows iterating over geometries and coatings without physical prototypes. We recommend using steels with a high yield strength and nitriding treatments to delay crack initiation. The predictive model validates that a larger curvature radius at the tip reduces stress concentration and doubles the cycles to failure.
How does the accumulation of cyclic plastic deformation in the microstructure of forced-entry tool steel affect the predictive accuracy of finite element fatigue models?
(PS: Material fatigue is like yours after 10 hours of simulation.)