In this study, the total algorithm of the strength-based design of the system for mass production has been developed. The proposed algorithm, which includes numerical, analytical, and experimental studies, was implemented through a case study on the strength-based structural design and fatigue analysis of a tractor-mounted sunflower stalk cutting machine (SSCM). The proposed algorithm consists of a systematic engineering approach, material selection and testing, design of the mass criteria suitability, structural stress analysis, computer-aided engineering (CAE), prototype production, experimental validation studies, fatigue calculation based on an FE model and experimental studies (CAE-based fatigue analysis), and an optimization process aimed at minimum weight. Approximately 85% of the system was designed using standard commercially available cross-section beams and elements using the proposed algorithm. The prototype was produced, and an HBM data acquisition system was used to collect the strain gage output. The prototype produced was successful in terms of functionality. Two- and three-dimensional mixed models were used in the structural analysis solution. The structural stress analysis and experimental results with a strain gage were 94.48% compatible in this study. It was determined using nCode DesignLife software that fatigue damage did not occur in the system using the finite element analysis (FEA) and experimental data. The SSCM design adopted a multi-objective genetic algorithm (MOGA) methodology for optimization with ANSYS. With the optimization solved from 422 iterations, a maximum stress value of 57.65 MPa was determined, and a 97.72 kg material was saved compared to the prototype. This study provides a useful methodology for experimental and advanced CAE techniques, especially for further study on complex stress, strain, and fatigue analysis of new systematic designs desired to have an optimum weight to strength ratio.

No abstract

No abstract

In this research, stress measurement tests and advanced application algorithms based on computer-aided design and engineering (CAD and CAE) were developed and tested. The algorithm was put implemented through a case study on the strength-based structural design and fatigue analysis of a chassis. This algorithm consists of numerical and experimental methods and additionally includes material tests, three-dimensional CAD, a finite element method (FEM)-based analysis procedures, a structural optimization strategy, prototype production, stress tests, a fatigue analysis, and design verification procedures. In the optimization study targeting the optimum chassis weight/strength ratio, two chassis prototypes, with 8 mm and a 5 mm wall thicknesses, were manufactured to verify the structural analysis and experimental tests. As a result of the FEA analyses, for 20 kN, which is the target load value of the chassis, for chassis thicknesses t = 5 mm and t = 8 mm, the maximum tensile strength was obtained as 93 MPa and 83 MPa, respectively. Thus, the material gain of 35.85 kg mass was achieved, and chassis utilization efficiency was increased. This research provides a useful methodology for experimental and advanced CAE techniques, especially for further research on complex stress and deformation analysis of chassis that are desired to be of optimum weight/strength ratio.

Computer aided engineering analysis is commonly used to evaluate and improve the performance and reliability of the products in today's manufacturing industry. Computer aided engineering analysis software use finite elements method in their solutions. The most significant problem in practicing these analyses is to form the mesh structure properly. The aim of this study is to research the effects of using surface and three-dimensional solid models in structural stress analysis. In this context, the maximum deformation in a square beam subjected to bending was calculated analytically and numerically. The solid model and surface model were created via CATIA. These models were analyzed under the same conditions in the static analysis module via ANSYS workbench. A difference of 1.32 % was detected between the numerical solution and the numerical displacement value of the surface model, and a difference of 11.84 % was detected between the numerical solution and the displacement value of the solid model. The difference between the von mises stress values of both models is approximately 30 %. In the parametric assessment conducted regarding the change in the mesh size, it was discovered that the results were affected by the mesh size significantly, and the mesh size and stress increased by 1550 % with the singularity problem in the solid model. In systems subjected to bending, using a shell mesh with 6 degrees of freedom is more advantageous in terms of solution time, operational capacity, stability and accuracy of the result.

No abstract

The laser beam, plasma arc, and oxygen cutting methods are widely used in metal cutting processes. These methods are quite different from each other in terms of initial setup cost and cutting success. A powered laser beam is used in laser beam cutting, plasma is used in plasma arc cutting, flammable gas - oxygen mixture is used in the oxygen cutting method. In this study, the cutting success of these methods was investigated on tensile specimens. Microstructure, hardness (HV 0.1), surface roughness, and strengths were investigated after the cutting process. The tensile test implemented with tensile samples cut from the same material by these three methods, it was observed that the strength values of the samples changed by about 8% in tensile strength depending on the cutting process. The hardness of the cut surfaces in plasma arc cutting increased from 150 HV to 230 HV for S235JR material. For this reason, it is difficult to perform machining operations after plasma cutting. The hardness value reached after laser beam cutting is 185 HV. Plasma arc cutting is more cost-effective than laser beam cutting. 1-3° vertical inclination (conicity) occurs on the cut surface in plasma arc cutting, while this inclination almost does not occur in laser cutting. In plasma cutting benches, cutting is done with oxygen, and in cutting with oxygen, the taper is seen in a small amount.

No abstract