Peening

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

Realistic Finite Element Simulations of Arc-Height Development in Shot-Peened Almen Strips

Abstract: It is the objective of this study to conduct realistic simulations of the arc-height development in shot-peened Almen strips using the finite element (FE) method. Unlike our earlier work which is devoted to relaxation of shot peening induced residual stress, in this paper, the focus is on peen forming as a result of repeated spherical impingement. Specifically, a 3D FE model with 1500 randomly distributed shots bombarding an Almen strip was developed. Strain rate dependent plasticity was considered and an artificial material damping was applied to control the undesired high-frequency oscillations. The solution further adopts both explicit dynamic and implicit quasi-static analyses to simulate the entire arc-height development in the Almen strips. Quantitative relationships between the resulting equivalent plastic strain and the associated residual stress distribution for a given shot velocity and shot numbers are established and discussed. The work also considers the effect of repeated impacts upon the induced residual stress field using a large number of random shots. Attention was further devoted to the effect of the strip constraint upon the outcome of the impingement. Our results indicate that the proposed FE model is a powerful tool in investigating the underlying mechanisms of the peening treatment. [DOI: 10.1115/1.4028006]

Influence of specimen thickness on the fatigue behavior of notched steel plates subjected to laser shock peening

Abstract: The influence of specimen thickness on the fatigue crack initiation of 2205 duplex stainless steel notched specimens subjected to laser shock peening (LSP) was investigated. The purpose was to examine the effectiveness of LSP on flat components with different thicknesses. For the LSP treatment a Nd:YAG pulsed laser operating at 10 Hz with 1064 nm of wavelength was used; pulse density was 2500 pulses/cm2. The LSP setup was the waterjet arrangement without sample coating. Residual stress distribution as a function of depth was determined by the hole drilling method. Notched specimens 2, 3 and 4 mm thick were LSP treated on both faces and then fatigue loading was applied with R = 0.1. Experimental fatigue lives were compared with life predictions from finite element simulation. A good comparison of the predicted and experimental fatigue lives was observed. LSP finite element simulation helps in explaining the influence of thickness on fatigue lives in terms of equivalent plastic strain distribution variations associated with the change in thickness. It is demonstrated that specimen size effect is an important issue in applying LSP on real components. Reducing the specimen thickness, the fatigue life improvement induced by LSP is significantly increased. Fatigue life extension up to 300% is observed on thin specimens with LSP.

Improvement of strength and reliability of ceramics by shot peening and crack healing

Abstract: In this study we propose a new method for improving the surface strength and reliability of ceramics that combines shot peening with crack-healing ability. We used Si 3 N 4 /SiC composite ceramics with high crack-healing ability and subjected the specimens to shot peening and crack healing. To evaluate the effect of our method, we investigated the residual stress after shot peening and crack healing and examined the specimens’ mechanical properties, including apparent fracture resistance, contact strength and bending strength. We found that shot peening and crack healing is effective to increase apparent fracture resistance, contact strength and bending strength.

Parametric Study on Single Shot and Overlapping Laser Shock Peening on Various Metals via Modeling and Experiments

Abstract: Laser shock peening (LSP) under water confinement regime involves several complicated physical phenomena. Among these phenomena, the interaction between laser and coating material during LSP is very important to the laser-induced residual stress, which has an important effect on the fatigue and corrosion properties of the substrate material. To gain a better understanding of this interaction, a series of experiments, including single shot, single-track overlapping, and multitrack overlapping LSP, has been carried out on various metals with different coatings. A 3D finite element model has also been developed to simulate the LSP process. Combining this with a previously developed confined plasma model, which has been verified by the experimental data from literature, the 3D finite element model is used to predict the residual stresses induced in the substrate material as well as the indentation profile on the substrate surface. The model prediction of indentation profiles is compared with the experimental data. The residual stresses in the depth direction are also validated against the X-ray diffraction measurement data for 4140 steel and Ti-6Al-4V, and good agreements are obtained for both predictions. The effect of process parameters on the residual stress is also investigated both experimentally and theoretically. [DOI: 10.1115/1.4002850]