Peening

About: Peening is a research topic. Over the lifetime, 5538 publications have been published within this topic receiving 73073 citations.

Mathematical Modeling of Ultra-High-Pressure Waterjet Peening

Abstract: Waterjet peening is a recent promising method in surface treatment. It has the potential to induce compressive residual stresses that benefit the fatigue life of materials similar to the conventional shot peening process. However, there are no analytical models that incorporate process parameters (i.e., supply pressure, jet exposure time, and nozzle traverse rate, etc) to allow predicting the optimized peering process. Mathematical modeling of high-pressure waterjet peening was developed in this study to describe the relation between the waterjet peening parameters and the resulting material modifications. Results showed the possibility of using the proposed mathematical model to predict an initial range for effective waterjet peening under the variation of waterjet peening conditions. The high cycle fatigue tests were performed to validate the proposed model and fatigue test results showed good agreement with the predictions.

Precision deep peening with mechanical indicator

Abstract: An apparatus produces compressive stress in a component surface. Positioning of a contact area of the component surface is controlled to situate a contact area of the component surface relative to an indenter element. The indenter element is fixtured to cause an indentation at the contact area. The force of the indentation is measured as the indenter element contacts the contact area, and controlled responsive to the amount of force measured and the desired compression. The system allows deep compressive stresses to be generated without the surface damage associated with conventional peening.

Laser pulse transmission through the water breakdown plasma in laser shock peening

Abstract: Laser shock peening (LSP) under a water confinement regime can produce plasma pressures on the target surface four times higher and 2–3 times longer than that under direct regime configurations. However, when the laser power density is above some threshold, a breakdown plasma occurs in water, which screens a significant amount of the incident laser pulse and therefore limits the magnitude and duration of the pressure induced on the target surface. A self-closed numerical model that can simulate the laser pulse transmission through the breakdown plasma generated in water during LSP has rarely been reported in literature. In this work, the breakdown plasma is simulated by solving an electron rate equation coupled with a Maxwell’s wave equation. The peak irradiance and duration of the laser pulse transmitted through the breakdown plasma predicted from the model can be correlated reasonably well with experimental data for 25 ns-1064 nm laser pulses. This model is then coupled with a previously developed thermal model for LSP to calculate the pressure pulse induced on the target surface. The trend of the pressure saturation and the pressure pulse duration decrease beyond some threshold laser irradiance is captured successfully by the model, and good agreements with experimental data have been obtained under a variety of LSP conditions.