Ján Slota

Experimental and Numerical Analysis of Local Mechanical Properties of Drawn Part

In this study, numerical and experimental results of deep drawing process were compared. Drawn part, used in automotive industry was drawn and measured using ARGUS measurement system, which works on a digital image correlation method (DIC). In order to optimize and verify accuracy of a numerical simulation results, this process was modeled in two codes which work on principle of the finite element method (FEM). Two types of FEM codes were used. Code which works on base of both, implicit and explicit time integration scheme, were used for calculation. Results were compared and discussed.

Optimization of FDM Prototypes Mechanical Properties with Path Generation Strategy

This paper present result of a study evaluating the influence of path generation strategy on mechanical properties of Fused Deposition Modeling (FDM) prototypes. Several scientific studies were researching the problematic of path generation and internal structure of FDM prototypes. Mostly the influence on mechanical properties was observed. This paper is aimed on determine the influence of outline number and internal air-gap on tensile strength of parts built from ULTEM 9085. For this two variables was determined the influence on built time and consumption of modeling material. Result show that proper model orientation when the orientation of load is known, can help to reduce the build time and material consumption.

Flexural Properties of FDM Prototypes Made with Honeycomb and Sparse Structure

The rapid prototyping (RP) process is capable of building parts of any complicated geometry in least possible time without incurring extra cost due of absence of tooling. Fused deposition modeling (FDM) is a fast growing RP technology due to its ability to build functional parts having complex geometrical shape in reasonable time period. The quality of built parts depends on many process variables. The presented study focus on assessment of mechanical property flexural strength of part fabricated using fused deposition modeling (FDM) technology. The 3-point bending test was used, to determine flexural strength. Samples were made of polycarbonate on Fortus 400 mc machine from polycarbonate with slice height 0.127mm. The experiment was focused on influence of air-gap size between fibers and number of outline contours on selected mechanical properties of FDM prototypes determined 3-point bending test. The results show possibility to obtain weight reduction in printed parts with sparse structure with sufficient flexural strength and with reduced build time, compared to structure printed with default machine setting,. To obtain optimal processing parameters for 3D printing prototypes, it is necessary to execute further experiments, which could verify gathered results.

Local Strain Hardening and Non-Uniformity of Plastic Strain of Tinplate

During evaluation of the mechanical properties of tinplate for packaging industry by uniaxial tensile test, a non-uniform plastic strain occurs very often. This phenomenon results from the fact, that the plastic deformation is not uniformly developed throughout the measured section. There is a localization of deformation in one or more places resulting in local changes of the tinplate ́s mechanical properties. This paper deals with local strain hardening and non-uniformity of plastic strain of the tinplate temper TH415CA during uniaxial tensile test. Based on micro hardness measurements in the following locally deformed areas, local changes of mechanical properties of the tinplate were determined. The reasons of early strain localization were assumed by microstructural analysis. In the present work are considering partial aspects of the problem focusing on the properties of the local strain hardening and their consequences for stability of uniform plastic strain.

THE SENSITIVITY OF A PHOTOGRAMMETRIC METHOD IN FORMABILITY ANALYSIS

Abstract Nowadays is a possible to implement numerical simulation and photogrammetric inspection to the complex process chain of inspection. In the recent years there has been significant progress in accuracy improving of these methods of inspection in pre-production or post-production stage of manufacturing. This article discusses these two methods from sensitivity and comparison point of view. Most attention has been paid to the photogrammetric method and his sensitivity to using different approaches. Results were compared with the result of numerical simulation and experiment. Numerical simulation was performed in static implicit finite element code Autoform. For this purpose, GPS cover of galvanized steel of DQ category was used for inspection. In this paper was proved that photogrammetric method of strain measurement is highly sensitive on the various external factors. Further results and findings are included in the next chapters of this paper

Experimental and Numerical Analysis of Springback Behavior of Aluminum Alloys

Presented work deals with springback behavior of two different aluminum alloys, one falling into 5th series (AW-5754 H22) with a thickness of 0.8 mm and other from 6th series (AW-6082 T6) with 1.0 mm thickness. These materials are used for their various applications and hardening process. The springback behavior was investigated by U-bending test. Bending tool was graduated jig with rollers and experiment was performed on R11 and R17 radii. The first series of specimens were oriented in a parallel direction and the other in a direction perpendicular to the rolling direction. Experimental results were measured with MATLAB measuring method and compared with finite element calculation carried out in PAM-STAMP. Influence of different yield functions was also examined.

Structure and tensile properties evaluation of samples produced by Fused Deposition Modeling

Abstract This paper presents the result of a study evaluating the influence of alternative path generation strategy on structure and some mechanical properties of parts produced by Fused Deposition Modeling (FDM) technology. Several scientific investigations focused on resolving issues in FDM parts by modifying a path generation strategy to optimize its mechanical properties. In this study, an alternative strategy was proposed with the intention of minimizing internal voids and, thus, to improve mechanical properties. Polycarbonate samples made by this alternative path generation strategy were subjected to tensile strength test and metro-tomography structure evaluation. The results reveal that the structure observed on build models differs from a structure expected from path generation predicted by software Insight 9.1. This difference affected the tensile strength of samples.

Optical Investigation of Component Made by FDM Technology

3D printed plastic components are nowadays frequently used parts in all areas of industrial sphere. These components are often made by FDM technology. The main advantage of this technology is quick manufacturing process, price and also possibility of producing complex parts. This paper is aimed to the component made by FDM technology from the view of their strength. Specially designed chair was loaded by different force and the maximum load before destruction was measured. Chair was under inspection of two different optical strain measurement systems working on different principles. System PONTOS working on the principle of digital photogrammetry and system ARAMIS working on the principle of digital image correlation were used. These systems were used in order to investigate and identify weak places of this chair.

Wrinkling Prediction and Optimization of Sheet Metal Forming Process by Numerical Simulation

The paper deals with optimization of forming process for AISI 430 stainless steel with nominal thickness 0.4 mm. During forming of sidewall for washing machine drum, some wrinkles remain at the end of forming process in some places. This problem was solved by optimization the geometry of the drawpiece using numerical simulation. During optimization a series of modifications of the part geometry to absolute elimination of wrinkling was performed. On the basis of mechanical tests, the material model was created and imported into the material database of Autoform simulation software.

Measurement of the Limit Strains on TS 245 Tinplate

The paper deals with measurement of limit strains for tinplate TS 245 made by US Steel with nominal thickness 0.3 mm. The FLC curve has been measured by implementation of Nakajima test on testing device Erichsen 145-60. The Nakajima test has been measured according to EN ISO 12004-2. Limit strains have been measured using 3D photogrammetric system Argus by GOM. Forming limit curve was evaluated in the software Argus. During test, some problems have been solved concerning friction on hemispherical punch which affected fracture position on the dome. Reached FLC curve was implemented in material database of PAM-Stamp 2G simulation software.