Pengaruh Ukuran Dan Jumlah Elemen Singular Terhadap Harga Faktor Intensitas Tegangan Untuk Kasus Retak Pojok Eliptik Dengan Metode Elemen Hingga

Stress intensity factor evaluation is needed to evaluate residual strength and crack growth. It developes some methods to evaluate stress intensity factor. In this research, the stress intensity factor is evaluated on the case of part through crack in finite solid with configuration of quarter elliptic corner crack. It is done by ANSYS software which based on finite element method. Crack tip element model is chosen a quarter point isoparametric 20 node three dimension. The result of ANSYS analysis gives the geometry factor (â) close enough to geometry factor (â) of BEASY software result, with maximum error of 7.99% for the 90o - angle. On the other side, comparation of the ANSYS result with the result of Newmann-Raju equation, the error maximum is 3.89% for the 0o -angle. From statistical test is known that the selection of singular element size and number, disposed doesn\u27t seem to influence the result of stress intensity factor calculation

Numerical Procedure for Modeling Crack Closure Induced Plasticity

Numerical procedures are utilized to predict crack closure-induced plasticity on planar surfaces. Skinner's algorithm is presented as an APDL macro command set. Procedures for controlling element size are developed to ensure the continuity of element size gradation. A loading generator is constructed using the *dim parameter, and the Newman model is explored for comparison. The analysis, based on conducted research, yields results lower than 0.05Sy

Modeling of Critical Blank Holder Force Based on a Gap Limit and Unbending Strain Energy in Deep Drawing Process

This study is aimed to predict the minimum varying blank holder force (VBHF) during the punch stroke, in order to eliminate wrinkle on cup deep drawing product. The slab method was used to develop mathematical modeling of the minimum VBHF base on a gap limit and unbending energy. The mathematical modeling has been validated to FE simulations for the prevention of wrinkling in the same criterion. Steel sheet of SPCD grade with thickness of 0.2 mm is used to generate the cylindrical cup shaped product with 40 mm diameter. Analytical Results of minimum VBHF have a similar trend result compared to FE simulation. However, the minimum VBHF can be quite effective for preventing the occurrence of excessive wrinkl

Simulation of Semi-Active the Blank Holder Force Control to Prevent Wrinkling and Cracking in Deep Drawing Process

This paper presents simulation of drawing force and thickness deformation in deep drawing which employs semi-active blank holder force control system, to solve the problem of cracking and wrinkling. The method of slab with feed back control failure criteria, was employed to make the modeling system and the semi-active blank holder to prevent wrinkling and cracking in forming low carbon steel sheet, without lubrication (=0.4). In this study, the mechanical properties of the material were chosen since that they equivalent to those of low carbon steel with its thickness of 0.2 mm, K= 572 N/mm2, UTS= 391 N/mm2, yield stress= 309 N/mm2 and n= 0.2. The diameter and the depth of the cylindrical cup-shaped product were 40 mm and 10 mm, respectively. Results from simulation have shown that the semi-active blank holder system can control very responsive against changing of deformation condition. The optimum of initial blank holder force is approximately 3000 N up to 4000 N. In the early stages (initial stroke), blank holder force system could be responsive to prevent cracking, and at the end of the punch stroke, it is very effective to prevent wrinkling. Simulation of semi-active blank holder force control system is excellent in model formation to prevent cracking and wrinkling

ANALISIS DAN EKSPERIMEN BLANK HOLDER GAP MINIMUM PADA PROSES RECTANGULAR CUP DEEP DRAWING

This paper aims to investigate the magnitude of minimum blank holder gap to prevent wrinkles and cracks defects of the rectangular cup with T4 material Tin Plate CA. Punch-die domensions are determined based on the standard tool designed. The methods of this research are an analytic, finite element (FE), and experimental approach, respectively. Each method in this study had been mutually compared to other methods. According to the research, minimum blank holder gap is recommended by 120% to 130% of the thickness of the initial material (about 0.24 ÷ 0.26 mm). By using the value of this gap, the height of wrinkles is very small, and the magnitude of the drawing force is still below the critical limit, so the product does not occur wrinkles and cracks

Analytical study and FEM simulation of the maximum varying blank holder force to prevent cracking on cylindrical cup deep drawing

This Research is aimed to predict the maximum varying blank holder force (VBHF) over the punch stroke in order to eliminate cracks on cup deep drawing product. The constant blank holder force during the process, it’s frequently not capable to prevent cracking, effectively. Using the slab method with assuming a constant volume of material, the simple analytical approach of maximum VBHF, has been conducted under the failure deformation and cracking criteria on every stage punch stroke. The cracking criteria are based on the maximum strength of materials. Steel sheet of SPCD grade, thickness 0.2 mm was used in this study. And the diameter of the cylindrical cup-shaped product was 40 mm. The analytic calculation of the maximum VBHF has been compared to FEM simulations, and its effects in the prevention of cracking. Analytical Results of maximum VBHF, not much different with FEM simulation. Compared to the application of the constant blank holder force, VBHF can be quite effective for preventing the occurrence of cracking and increasing the formability of deep drawing

Modeling of the minimum variable blank holder force based on forming limit diagram (FLD) in deep drawing process

This paper presents the mathematical approach of minimum blank holder force to prevent wrinkling in deep drawing process of the cylindrical cup. Based on the maximum of minor-major strain ratio, the slab method was applied to determine the modeling of minimum variable blank holder force (VBHF) and it compared to FE simulation. The Tin steel sheet of T4-CA grade, with the thickness of 0.2 mm was used in this study. The modeling of minimum VBHF can be used as a simple reference to prevent wrinkling in deep drawing

Effect of Transfer Time During Austempering of Nodular Cast Iron FCD 450

Austempered Ductile Iron (ADI) requires accurate process control regarding temperature and time. In reality however, there is one parameter that is often disregarded. The parameter is transfer time, i.e. time that is used to transfer nodular cast iron from austinizing furnace into salt bath furnace. The aim of the experiment is to investigate the effect of transfer time on the mechanical properties and microstructures of austempered nodular cast iron FCD 450. The FCD 450 was austenized at 900°C for 1 hour, then transferred to a salt bath furnace for austempering process with transfer time variation of 15, 68, and 120 seconds. Austempering was carried out at 316°C for 1 hour. Results showed that longer transfer time tended to decrease the hardness and impact energy of the austempered FCD 450.The tendency rose from the decrease of bainite content due to the longer transfer time as indicated by the microstructures