scholarly journals Optimization of shot peen forming patterns to achieve complex target shapes the inverse problem

2021 ◽  
Author(s):  
Hong Yan Miao ◽  
Martin levesque ◽  
Frederick Gosselin
Keyword(s):  
Inverse Problem ◽  
Optimization Procedure ◽  
Spherical Shape ◽  
Forming Process ◽  
Peen Forming ◽  
Out Of Plane ◽  
Order Of Magnitude ◽  
Complex Target ◽  
Wing Skin ◽  
Relative Differences

The inverse problem of determining how to shot peen a plate such that it deforms into a desired target shape is a challenge in the peen forming industry. While peening thick plates uniformly on one side results in a spherical shape, with the same curvature in all directions, complex peening patterns are required to form other shapes, such as cylinders and saddles found on fuselages and wing skin panels. In this study, we present an optimization procedure to automatically compute shot peening patterns. This procedure relies on an idealized model of the peen forming process, where the effect of the treatment is modeled by in-plane expansion of the peened areas, and on an off-the-shelf optimization algorithm. For validation purposes, we peen formed three 305 X 305 X 4.9 mm and two 762 X 762 X 4.9mm 2024--T3 aluminium alloy plates into cylindrical and saddle shapes using the same peening treatment. The obtained shapes qualitatively match simulations. For 305 X 305 X 4.9mm plates, the relative differences had the same distribution and were of the same order of magnitude as initial out-of-plane deviations measured on the as-received plates.

Numerical modeling of a wing skin peen forming process

1996 ◽  
Vol 5 (6) ◽  
pp. 753-760 ◽  
Author(s):  
R. D. VanLuchene ◽  
E. J. Cramer
Keyword(s):  
Numerical Modeling ◽  
Forming Process ◽  
Peen Forming ◽  
Wing Skin

scholarly journals Determination of optimal shot peen forming patterns using the theory of non-Euclidean plates

2021 ◽  
Author(s):  
Vladislav Sushitskii ◽  
Wim M van Rees ◽  
Martin levesque ◽  
Frederick Gosselin
Keyword(s):  
Inverse Problem ◽  
Theoretical Approach ◽  
Theoretical Framework ◽  
Forward Problem ◽  
Test Cases ◽  
Practical Realization ◽  
Forming Process ◽  
Target Shape ◽  
Peen Forming

We show how a theoretical framework developed for modelling nonuniform growth can model the shot peen forming process. Shot peen forming consists in bombarding a metal panel with multiple millimeter-sized shot, that induce local bending of the panel. When applied to different areas of the panel, peen forming generates compound curvature profiles starting from a flat state. We present a theoretical approach and its practical realization for simulating peen forming numerically. To achieve this, we represent the panel undergoing peen forming as a bilayer plate, and we apply a geometry-based theory of non-Euclidean plates to describe its reconfiguration. Our programming code based on this approach solves two types of problems: it simulates the effect of a predefined treatment (the forward problem) and it finds the optimal treatment to achieve a predefined target shape (the inverse problem). Both problems admit using multiple peening regimes simultaneously. The algorithm was tested numerically on 200 randomly generated test cases.

scholarly journals Magneto-optical design of anomalous Nernst thermopile

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Wang ◽  
Asuka Miura ◽  
Rajkumar Modak ◽  
Yukiko K. Takahashi ◽  
Ken-ichi Uchida
Keyword(s):  
Optical Design ◽  
Polarized Light ◽  
Ferromagnetic Material ◽  
Light Polarization ◽  
Optical Recording ◽  
Induced Voltage ◽  
Large Area ◽  
Circularly Polarized Light ◽  
Out Of Plane ◽  
Order Of Magnitude

AbstractThe introduction of spin caloritronics into thermoelectric conversion has paved a new path for versatile energy harvesting and heat sensing technologies. In particular, thermoelectric generation based on the anomalous Nernst effect (ANE) is an appealing approach as it shows considerable potential to realize efficient, large-area, and flexible use of heat energy. To make ANE applications viable, not only the improvement of thermoelectric performance but also the simplification of device structures is essential. Here, we demonstrate the construction of an anomalous Nernst thermopile with a substantially enhanced thermoelectric output and simple structure comprising a single ferromagnetic material. These improvements are achieved by combining the ANE with the magneto-optical recording technique called all-optical helicity-dependent switching of magnetization. Our thermopile consists only of Co/Pt multilayer wires arranged in a zigzag configuration, which simplifies microfabrication processes. When the out-of-plane magnetization of the neighboring wires is reversed alternately by local illumination with circularly polarized light, the ANE-induced voltage in the thermopile shows an order of magnitude enhancement, confirming the concept of a magneto-optically designed anomalous Nernst thermopile. The sign of the enhanced ANE-induced voltage can be controlled reversibly by changing the light polarization. The engineering concept demonstrated here promotes effective utilization of the characteristics of the ANE and will contribute to realizing its thermoelectric applications.

scholarly journals Layer- and gate-tunable spin-orbit coupling in a high-mobility few-layer semiconductor

2021 ◽  
Vol 7 (5) ◽  
pp. eabe2892
Author(s):  
Dmitry Shcherbakov ◽  
Petr Stepanov ◽  
Shahriar Memaran ◽  
Yaxian Wang ◽  
Yan Xin ◽  
...  
Keyword(s):  
Electric Field ◽  
High Mobility ◽  
Orbit Coupling ◽  
Spin Splitting ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Quantum Oscillations ◽  
Out Of Plane ◽  
Order Of Magnitude ◽  
Spin Degeneracy

Spin-orbit coupling (SOC) is a relativistic effect, where an electron moving in an electric field experiences an effective magnetic field in its rest frame. In crystals without inversion symmetry, it lifts the spin degeneracy and leads to many magnetic, spintronic, and topological phenomena and applications. In bulk materials, SOC strength is a constant. Here, we demonstrate SOC and intrinsic spin splitting in atomically thin InSe, which can be modified over a broad range. From quantum oscillations, we establish that the SOC parameter α is thickness dependent; it can be continuously modulated by an out-of-plane electric field, achieving intrinsic spin splitting tunable between 0 and 20 meV. Unexpectedly, α could be enhanced by an order of magnitude in some devices, suggesting that SOC can be further manipulated. Our work highlights the extraordinary tunability of SOC in 2D materials, which can be harnessed for in operando spintronic and topological devices and applications.

Prediction and Optimization of Deformations in Coupling Mechanism Based Laser Forming of Sheet Metals

2019 ◽  
Vol 969 ◽  
pp. 552-557
Author(s):  
Kuntal Maji
Keyword(s):  
Process Parameters ◽  
Metal Forming ◽  
Three Dimensional ◽  
Laser Forming ◽  
Coupling Mechanism ◽  
Sheet Metals ◽  
Forming Process ◽  
Out Of Plane ◽  
Metal Forming Process ◽  
Plane Deformations

Fabricating three dimensional shaped surfaces from flat sheet metals by laser forming, both out-of-plane and in-plane deformations are required. This article presents the modeling of coupling mechanism activated laser forming of sheet metals based on experimental data for prediction and optimization of bending and thickening deformations. Experiments were performed based on a central composite design of experiments on coupling mechanism based laser metal forming process considering the input process parameters like laser power, scan speed and spot diameter, bending and thickening were taken as the outputs. Neural network and neuro-fuzzy system-based models were developed to carry out both forward and inverse modeling of the laser metal forming process under the coupling mechanism. Multi-objective optimization based on the non-dominated sorting genetic algorithm was used to obtain multiple optimal solutions to achieve different amounts of out-of-plane and in-plane deformations. The proposed method could guide for a suitable selection of the process parameters to produce three-dimensional shapes utilizing coupling mechanism-based laser forming using multiple laser line heating.

Anisotropic thermal conductivity of rare earth–transition metal thin films

1992 ◽  
Vol 7 (2) ◽  
pp. 329-334 ◽  
Author(s):  
L.J. Shaw-Klein ◽  
T.K. Hatwar ◽  
S.J. Burns ◽  
S.D. Jacobs ◽  
J.C. Lambropoulos
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Rare Earth ◽  
Transition Metal ◽  
Columnar Microstructure ◽  
Deposition Pressure ◽  
Metal Thin Films ◽  
Anisotropic Thermal Conductivity ◽  
Out Of Plane ◽  
Order Of Magnitude

Thermal conductivity measurements were performed on several amorphous rare earth transition metal thin films of varying microstructure. The thermal conductivity perpendicular to the plane of the film, measured by the thermal comparator method, was compared with the thermal conductivity value measured parallel to the plane of the film. The latter value was obtained by converting electrical conductivity values to thermal conductivity via the Wiedemann–Franz relationship. As expected, the columnar microstructure induced during the sputter deposition of the thin films causes an anisotropy in the thermal conductivity values, with the in-plane values consistently lower than the out-of-plane values. The effect is most pronounced for the more columnar films deposited at higher pressure, for which the in-plane thermal conductivity, 0.3 W/mK, is an order of magnitude lower than the out-of-plane thermal conductivity, 4.3 W/mK. The thermal conductivity out of the plane of the film decreased with increasing deposition pressure, due to the decreasing film density.

Deformation Rule of 7150 Aluminum Alloy Thick Plate by Pre-Stress Shot Peen Forming

2014 ◽  
Vol 1052 ◽  
pp. 477-481 ◽  
Author(s):  
Ming Tao Wang ◽  
Yuan Song Zeng ◽  
Xue Piao Bai ◽  
Xia Huang
Keyword(s):  
Aluminum Alloy ◽  
Metal Forming ◽  
Thick Plate ◽  
Radius Of Curvature ◽  
Al Alloy ◽  
Forming Process ◽  
Peen Forming ◽  
Metal Forming Process ◽  
Aeronautical Industry ◽  
Different Thickness

Pre-stress shot peen forming is a metal forming process widely used in aeronautical industry. The test parts of 7150 Al alloy of different thickness were pre-stress shot peen formed. The deformation rule of those parts was investigated by means of changing the peening coverage. The results show that the radius of curvature of the parts will enhance gradually with increasing of the plate’s thickness. In addition, enhancing peening coverage could raise the deformation in the case of that the thickness and peening parameters are unchanged. Furthermore, the minimum radius of curvature of the 8mm plate after saturation pre-stress shot peen forming could reach 499mm.

An Inverse Problem for the Mechanical Characterization of Steels From the Taylor Test

2010 ◽  
Author(s):  
C. Hernandez ◽  
A. Maranon ◽  
I. A. Ashcroft ◽  
J. P. Casas-Rodriguez
Keyword(s):  
Inverse Problem ◽  
Material Characterization ◽  
Impact Test ◽  
Kinematic Hardening ◽  
Optimization Procedure ◽  
Material Model ◽  
Hardening Material ◽  
Final Shape ◽  
Taylor Impact ◽  
Taylor Impact Test

Material characterization procedures are often complicated processes. In particular, dynamic material characterization usually requires many complicated and expensive tests. One of the tools used to characterize the behavior of materials under dynamic loading is the Taylor impact test. In this experiment, a flat-ended cylinder of initial uniform cross-sectional area is fired at a rigid target. The terminal geometry of the deformed cylinder is used to determine the material strength at different strain rates. This paper presents the formulation and solution of a first class inverse problem for the identification of the kinematic hardening material model from a Taylor impact test of a steel cylinder. The inverse problem is formulated as an optimization procedure for the determination of the optimal set of the model constants. The input parameter of the procedure is the final shape of a Taylor impact test specimen, in terms of central geometric moments, at a given impact velocity. The output parameters are the material model constants, which are determined by fitting the final shape of a numerically simulated Taylor specimen to the final shape of the experimental specimen. This optimization procedure is performed by a real-coded genetic algorithm. The paper includes a numerical example of the characterization procedure for a steel 1018 Taylor specimen of 8 mm diameter and 20 mm length, impacted at a velocity of 250 m/s. This simulation demonstrates the performance of the algorithm and the ability to estimate the kinematic hardening material model constants.

Three-Dimensional Numerical Simulation and Experimental Study of Sheet Metal Bending by Laser Peen Forming

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Yongxiang Hu ◽  
Yefei Han ◽  
Zhenqiang Yao ◽  
Jun Hu
Keyword(s):  
Numerical Model ◽  
Sheet Metal ◽  
Laser Energy ◽  
Three Dimensional ◽  
Target Surface ◽  
Thick Sheet ◽  
Specimen Thickness ◽  
Forming Process ◽  
Form Complex ◽  
Peen Forming

Laser peen forming (LPF) is a purely mechanical forming method achieved through the use of laser energy to form complex shapes or to modify curvatures. It is flexible and independent of tool inaccuracies that result from wear and deflection. Its nonthermal process makes it possible to form without material degradation or even improve them by inducing compressive stress over the target surface. In the present study, a fully three-dimensional numerical model is developed to simulate the forming process of laser peen forming. The simulation procedure is composed of several steps mainly including the shock pressure prediction, the modal analysis, and the forming process calculation. System critical damping is introduced to prevent unnecessary long post-shock residual oscillations and to greatly decrease the solution time for simulation. The bending profiles and angles with different thicknesses are experimentally measured at different scanning lines and scanning velocities to understand the process and validate the numerical model. The calculated bending profiles and angles agree well with the trend of the measured results. But it is found that simulations with the Johnson–Cook model are more consistent, matching the experimental results for the thick sheet metal with a convex bending, while the elastic-perfectly-plastic model produces a better agreement even though with underestimated values for the thinner sheet metal with a concave bending. The reason for this phenomenon is discussed, combining the effects of strain rate and feature size. Both the simulation and the experiments show that a continuous decrease in bending angle from concave to convex is observed with increasing specimen thickness in general. Large bending distortion is easier to induce by generating a concave curvature with LPF, and the angle of bending distortion depends on the number of laser shocks.

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