The effect of the roller profile oncave-in defect in reshaping processby considering nonlinear combine strain hardening

The reshaping process of pipes is an important method in producing non-circular pipes. Desired profile products are produced by passing round pipe through the rotating rollers. Cave-in defect is one of the common defects in the reshaping process. Roller design issues can decrease this kind of defect. In this paper, a method based on the slab method and the incremental plasticity has been presented to the numerical study of a 2D reshaping process. For investigating the Cave-in defect, the contact model has been developed. The concept of element elongation has been introduced to increase the accuracy of the contact model. Based on the presented method, numerical software has been developed to simulate the 2D reshaping process. Elastic-plastic equations for this subject have been driven based on the incremental method, J yielding criterion, and non-linear combined hardening. The effects of the radius of the roller profile on cave-in defects have been investigated by using the presented software (DARF). A set of experiments has been conducted in a forming station to verify the results. Results show that the presented model has higher accuracy than the Abaqus commercial software in predicting the cave-in defect. Based on the results of the model, the local increase of yielding stress directly affects the cave-in defect. Also, a meaningful relationship between the radius of the roller and the amount of the cave-in has been observed.

Study on Minimum Rollable Thickness in Asymmetrical Rolling

A new model for the asymmetrical rolling is proposed to calculate the minimum rollable thickness simply and fast by the slab method. The calculation formulas of the rolling pressure, the rolling force, the critical roll speed ratio and the critical front tension under different deformation zone configurations are proposed, and the deformation zone configuration - rolling parameters relationship diagram is given and analyzed. The results show that the minimum rollable thickness can be reached when the rolling parameters keep the deformation zone configuration as cross-shear zone + backward-slip zone (C+B) or all cross-shear zone (AC). The calculation formulas of the minimum rollable thickness and the required rolling parameters for different deformation zone configurations are proposed respectively. The calculated value is in good agreement with the experimental results.

REDESIGN BUILDING STRUCTURE RSGM UGM PROF. SOEDOMO USING FLAT SLAB METHOD WITH DROP PANELS

Flat slab is reinforced concrete plate construction without beam. Without using beam, the obtainable profit is to minimize concrete volume, height/floor, and structural load. Other profits are simpler and economic reinforcement, scaffolding, and formwork. In this study, structural redesign of RSGM UGM Prof. Soedomo Yogyakarta building was made by using flat slab method. The objective of this study was to find structural dimension of floor and roof plates as well as reinforcement of the RSGM UGM Prof. Soedomo Building using structural system of flat slab, dimension of structural column and drop panel as well as reinforcement of the RSGM UGM Prof. Soedomo Building using structural system of flat slab. This method was to redesign using flat slab method complying with the standard of SNI 2847-2013 and software ETABS 2017. The results of analysis and calculation of structural dimension using flat slab method showed floor plate thickness of 170 mm; roof plate thickness, 120 mm; drop panel thickness, 270 mm with drop panel width of 2000 mm in direction x and 1500 mm in direction y, as well as use of column dimension of 500 mm x 500 mm. The analysis using software ETABS 2016 showed building structure in period (T) of 1.07 seconds.Keywords: RSGM UGM Prof. Soedomo Building, Drop Panel, Flat slab.

Calculation methods of bridge deck for prestressed short rib T-beam bridges

Because of the low height of the prestressed short rib T-beam bridge and the poor torsion resistance of the main beam, the positive moment in the middle span of the bridge deck will increase correspondingly compared with the normal rib beam bridge. At present, there is little research on the calculation method of the bridge deck of the prestressed short rib T-beam bridge. In this paper, the space finite element method and the continuous one-way slab method are used to calculate the forces on the bridge deck, based on the space finite element method, a finite element elastic supported continuous beam method is proposed to calculate the forces on the bridge deck. By comparing the calculation results of the three methods with the test results, the reasonable calculation method of the bridge deck is studied. The results show that the spatial finite element analysis method can simulate the mechanical performance of the deck of the bridge of the prestressed short rib T-beam bridge well, the stress calculation results are consistent with the test results, and the calculation accuracy is high, which can be used in the actual engineering design; The finite element analysis method of elastic support continuous beam can also simulate the mechanical performance of the deck of the bridge of the prestressed short rib T-beam bridge. The concept of the method is clear, the calculation is convenient, and it is more suitable for the application of engineering design; The calculation results of the continuous one-way slab method are too large to be safe for design.