Inverse form finding with h-adaptivity and an application to a notch stamping process

The aim is to determine the optimized semi-finished workpiece geometry to its given target geometry after a forming process. Hereby, a novel approach for inverse form finding, a type of a shape optimization, is applied to a notch stamping process. As a special feature, h-adaptive mesh refinement is considered within the iteratively performed forming simulation

Application of a non-invasive form finding algorithm to the ring compression test with varying friction coefficients

It is a great challenge in the development of functional components to determine the optimal blank design (material configuration) of a workpiece according to a specific forming process, while knowing the desired target geometry (spatial configuration). A new iterative non-invasive algorithm, which is purely based on geometrical considerations, is developed to solve inverse form finding problems. The update-step is performed by mapping the nodal spatial difference vector, between the computed spatial coordinates and the desired spatial target coordinates, with a smoothed deformation gradient to the discretized material configuration. The iterative optimization approach can be easily coupled non-invasively via subroutines to arbitrary finite element codes such that the pre-processing, the solving and the post-processing can be performed by the habitual simulation software. This is exemplary demonstrated by an interacting between Matlab (update procedure) and MSC. MarcMentat (forming simulation). The algorithm succeeds for a parameter study of a ring compression test within nearly linear convergence rates, despite highly deformed elements and tangential contact with varying friction parameters

A non-invasive heuristic approach to shape optimization in forming

The aim is to determine—relating to a given forming process—the optimal material (undeformed) configuration of a workpiece when knowing the target spatial (deformed) configuration. Therefore, the nodal positions of a discretized setting based on the finite element method (FEM) are the discrete free parameters of the form finding problem. As a verification, inputting the determined optimal material nodal positions, a subsequent re-computation of the forming process should then result in exactly the target spatial nodal positions. A new, non-invasive iterative algorithm, which is purely based on the nodal data of each iteration, is proposed to determine the discretized optimal material configuration. Specifically, the L2 -smoothed deformation gradient at each discretization node is used to update the discretized material configuration by a transformation of the difference vectors between the currently computed and the target spatial nodal positions. The iterative strategy can be easily coupled in a non-invasive fashion via subroutines with arbitrary external FEM software. Since only the computed positions of the discretization nodes are required for an update step within the form finding algorithm, the procedure does not depend on the specific material modelling and is moreover applicable to arbitrary element types, e. g. solid- or solid-shell-elements. Furthermore the convergence rate for solving the form finding problem is nearly linear. This is demonstrated by examples that are realized by a coupling of Matlab (iterative update procedure) and MSC.Marc (external FEM software). Solving the form finding problem to determine an optimum workpiece design is of great interest especially for metal forming applications

A Fast Approach to Shape Optimization using the Inverse FEM

Inverse form finding aims to determine the optimum blank design of a workpiece whereby the desired spatial configuration that shall be obtained after a forming process, the boundary conditions and the applied loads are known. As a verification of the optimal material configuration a subsequent direct FEM computation has to result in the desired shape of the deformed workpiece. In this contribution the inverse FEM, which formulates the mechanical weak form in the spatial configuration Bt and solves it with respect to the material configuration B0, is used to obtain an admissible blank configuration. An example of applying this inverse method to a contact forming simulation is presented. To this end a FE-code applicable to use the inverse mechanical formulation is coupled with the commercial software MSC. Mentat. In the inverse computation the contact problem is approximated by displacement control

Torta de sacha inchi tratada con cloruro de sodio al 3% a diferentes tiempos de cocción y tiempos de remojo, en la alimentación de pollos de carne en Tingo María.

TesisEl experimento tuvo como objetivo determinar el comportamiento productivo y económico del uso de la torta de sacha inchi sometido al efecto combinado de diferentes tiempos de cocción en una solución de NaCI y tiempos de remojo, para la alimentación de pollos de carne en Tingo María. Sobre 96 pollos parrilleros (50% de cada sexo) de 7 días de edad con peso promedio de 284±21g, se evalúa los indicadores productivos y económico de pollos alimentados con torta de sacha inchi incluida en niveles: T1 = 0%, T2 = 5%, T3 = 8% y T4 = 8% en una ración balanceada. Con un diseño completamente al azar; con 4 tratamientos y 6 repeticiones (3 primeras repeticiones machos y el resto hembras); la unidad experimental estuvo conformada por 4 pollos. El análisis de varianza no detecto diferencias (test de Dunnett con 5% de confianza) entre tratamientos para consumo de alimento, ganancia de peso y conversión alimenticia, entre sexos el análisis detectó diferencias (test de Tukey con 5% de confianza). Los resultados a los 42 días para cada tratamiento fueron de T1: consumo de alimento 4088g, ganancia de peso 2251 g y conversión alimenticia 1.82; T2: consumo de alimento 4156g, ganancia de peso 2253g y conversión alimenticia 1.85; T3: consumo de alimento 4238g, ganancia de peso 2368g y conversión alimenticia 1.79; T4: consumo de alimento 4089g, ganancia de peso 2288g y conversión alimenticia 1.79. Pollos de ambos sexos que consumieron ración balanceada incluida de 8% de torta de sacha inchi procesada en cocción a 95°C durante 30 minutos en una solución de cloruro de sodio al 3% y con remojo de 12 horas en agua tuvieron mejor desempeño zootécnico y económico

Inverse form finding with H-adaptivity and an application to a notch stamping process

The aim is to determine the optimized semi-finished workpiece geometry to its given target geometry after a forming process. Hereby, a novel approach for inverse form finding, a type of a shape optimization, is applied to a notch stamping process. As a special feature, h-adaptive mesh refinement is considered within the iteratively performed forming simulation

Experimental Verification of a Benchmark Forming Simulation

Forming of near-net-shaped and load-adapted functional components, as it is developed in the Transregional Collaborative Research Centre on Sheet-Bulk Metal Forming SFB/TR 73, causes different problems, which lead to non-optimal manufacturing results. For these high complex processes the prediction of forming effects can only be realized by simulations. A stamping process of pressing eight punches into a circular blank is chosen for the considered investigations. This reference process is designed to reflect the main aspects, which strongly affect the final outcome of forming processes. These are the orthotropic material behaviour, the optimal design of the initial blank and the influences of different contact and friction laws. The aim of this work is to verify the results of finite element computations for the proposed forming process by experiments. Evaluation methods are presented to detect the influence of the anisotropy and also to quantify the optimal blank design, which is determined by inverse form finding. The manufacturing accuracy of the die plate and the corresponding roughness data of the milled surface are analysed, whereas metrological investigations are required. This is accomplished by the help of advanced measurement techniques like a multi-sensor fringe projection system and a white light interferometer. Regarding the geometry of the punches, micromilling of the die plate is also a real challenge, especially due to the hardness of the high-speed steel ASP 2023 (approx. 63 HRC). The surface roughness of the workpiece before and after the forming process is evaluated to gain auxiliary data for enhancing the friction modelling and to characterise the contact behaviour