scholarly journals Numerical investigation on the forming behaviour of stainless/carbon steel bimetal composite

2018 ◽  
Vol 185 ◽  
pp. 00012
Author(s):  
Zhou Li ◽  
Jingwei Zhao ◽  
Qingfeng Zhang ◽  
Sihai Jiao ◽  
Zhengyi Jiang
Keyword(s):  
Carbon Steel ◽  
Circumferential Stress ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Composite Sheet ◽  
Forming Process ◽  
Thickness Strain ◽  
Forming Simulation ◽  
Bimetal Composite ◽  
Forming Behaviour

Bimetal composites have wide applications due to their excellent overall performance and relatively low comprehensive cost. The aim of this study is to investigate the forming behaviour of stainless/carbon steel bimetal composite during stamping by finite element method (FEM). In this work, the bonding interface of bimetal composite sheet was assumed to be perfect without delamination during the plastic forming process for simplicity. Uniaxial tensile tests on base metal (carbon steel) and compositing metal (stainless steel) were first carried out, respectively, in order to obtain the tensile properties of each of the component materials required in the forming simulation. Processing variables, including the layer stacking sequence, relative thickness ratios of two layers and friction were considered, and their effects on the distributions of circumferential stress and thickness strain were analysed. The bimetal composite sheet was set as the eight-node solid elements in the developed FEM model, which is effective for evaluating the distributions of circumferential stress and thickness strain, and predicting the high-risk region of necking during the stamping of bimetal composites. The simulation results can be used as an evaluation indicator of the capability of forming machine to ensure the bimetal composite can be safely formed.

scholarly journals Performance of Thermo-Mechanically Processed AA7075 Alloy at Elevated Temperatures—From Microstructure to Mechanical Properties

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 884 ◽  
Author(s):  
Seyed Vahid Sajadifar ◽  
Emad Scharifi ◽  
Ursula Weidig ◽  
Kurt Steinhoff ◽  
Thomas Niendorf
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Forming Process ◽  
Softening Mechanism ◽  
Rate Dependent ◽  
Heat Treated ◽  
Different Temperatures ◽  
Die Forming

This study focuses on the high temperature characteristics of thermo-mechanically processed AA7075 alloy. An integrated die forming process that combines solution heat treatment and hot forming at different temperatures was employed to process the AA7075 alloy. Low die temperature resulted in the fabrication of parts with higher strength, similar to that of T6 condition, while forming this alloy in the hot die led to the fabrication of more ductile parts. Isothermal uniaxial tensile tests in the temperature range of 200–400 °C and at strain rates ranging from 0.001–0.1 s−1 were performed on the as-received material, and on both the solution heat-treated and the thermo-mechanically processed parts to explore the impacts of deformation parameters on the mechanical behavior at elevated temperatures. Flow stress levels of AA7075 alloy in all processing states were shown to be strongly temperature- and strain-rate dependent. Results imply that thermo-mechanical parameters are very influential on the mechanical properties of the AA7075 alloy formed at elevated temperatures. Microstructural studies were conducted by utilizing optical microscopy and a scanning electron microscope to reveal the dominant softening mechanism and the level of grain growth at elevated temperatures.

scholarly journals Determination of the Plastic Strain by Spherical Indentation of Uniaxially Deformed Sheet Metals

2015 ◽  
Vol 651-653 ◽  
pp. 950-956 ◽  
Author(s):  
Mohamad Idriss ◽  
Olivier Bartier ◽  
Gérard Mauvoisin ◽  
Charbel Moussa ◽  
Eddie Gazo Hanna ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Accurate Determination ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Spherical Indentation ◽  
Instrumented Indentation ◽  
Forming Process ◽  
Hardening Law ◽  
Indentation Tests

This work consists of determining the plastic strain value undergone by a material during a forming process using the instrumented indentation technique (IIT). A deep drawing steel DC01 is characterized using tensile, shear and indentation tests. The plastic strain value undergone by this steel during uniaxial tensile tests is determined by indentation. The results show that, the identification from IIT doesn’t lead to an accurate value of the plastic strain if the assumption that the hardening law follows Hollomon law is used. By using a F.E. method, it is shown that using a Voce hardening law improves significantly the identification of the hardening law of a pre-deformed material. Using this type of hardening law coupled to a methodology based on the IIT leads to an accurate determination of the hardening law of a pre-deformed material. Consequently, this will allow determining the plastic strain value and the springback elastic strain value of a material after a mechanical forming operation.

Predicting Edge Cracks on Shear-Cut High-Strength Steels by Modified Uniaxial Tensile Tests

2016 ◽  
Vol 703 ◽  
pp. 49-55 ◽  
Author(s):  
Martin Feistle ◽  
Isabella Pätzold ◽  
Roland Golle ◽  
Wolfram Volk
Keyword(s):  
Tensile Test ◽  
Measurement Method ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Forming Process ◽  
Contact Measurement ◽  
Edge Cracks ◽  
Near Future

During the forming of high-strength steels, edge cracks occur unexpectedly on sheared edges e.g. during collar forming. A non-contact measurement method based on the well-known tensile test was developed. It allows the investigation of the formation of edge cracks under tensile loads and determining general criteria to predict the formation of edge cracks during a specific forming process. The criteria are validated experimentally by means of the collar-forming test. In conjunction with the proposed line-fit-method these criteria can be implemented easily in FEM software in the near future for the prediction of edge cracks.

Application of Dic Technique for Monitoring of Deformation Process of Spr Hybrid Joints / Zastosowanie Techniki Dic Do Obserwacji Procesu Deformacji Hybrydowych Połaczen Typu Spr

2013 ◽  
Vol 58 (1) ◽  
pp. 119-125 ◽  
Author(s):  
T. Sadowski ◽  
M. Knec
Keyword(s):  
Deformation Process ◽  
Load Capacity ◽  
Tensile Tests ◽  
Lap Joints ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Specimen Preparation ◽  
Forming Process ◽  
Absorption Increase ◽  
Dic Technique

Digital Image Correlation (DIC) technique gives possibility to observe deformation process in many applications including self-piercing riveting (SPR) hybrid joint. The hybrid SPR joint consists of simple SPR joint made of two adherends, steel tubular rivet (total length of 5 mm) and an adhesive. The adhesive was applied before piercing process. For specimen preparation two different aluminum alloys were used: 2024 and 5005 (2mm thickness both) with tensile strength 400 and 160MPa, respectively. For better understanding of joint forming process and to allow DIC strains observation during the joint creation, a special holder was designed with precisely polished die. The tests were performed by application of the 100kN servo-hydraulic machine, which recorded time, load, displacement and was synchronized with the DIC system. The joint forming process was carried out with 2 mm/min constant speed. During piercing process rivet and upper surface of the adherend were observed and the major strain states were estimated. The uniaxial tensile tests of single lap joints (SLJ) up to the final failure were performed and the displacements and the strains were recorded. In particular the rivet deformation was observed also during the whole loading process. The hybrid SPR joints are very effective, because the load capacity and energy absorption increase more than 1.5 times in comparison to the simple SPR joints.

Grain Size Effect on Fracture Behavior of the Axis-Tensile Test of Inconel 718 Sheet

2016 ◽  
Vol 35 (10) ◽  
pp. 989-998 ◽  
Author(s):  
B.B. Liu ◽  
J.Q Han ◽  
R. Zhao ◽  
W. Liu ◽  
M. Wan
Keyword(s):  
Grain Size ◽  
Size Effect ◽  
Inconel 718 ◽  
Fracture Morphology ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Specimen Thickness ◽  
Forming Process ◽  
Fracture Behaviors ◽  
Micro Parts

AbstractChange in mechanical parts from macro-size to micro-size has become a trend in the metal- and alloy-forming process, with an increasing demand on micro-parts in the last decades. The material mechanical behaviors of micro-size parts are quite different from the conventional ones of macro-size parts due to size effect. It is necessary to further investigate the effects of grain size on material mechanisms in micro-scales, especially fracture behaviors. The fracture behaviors of Inconel 718 sheet with the thickness of 300 μm are studied by uniaxial tensile tests in different grain sizes ranging from 18 to 130 μm. The results show that fracture stress and strain decrease with the increase of grain size. A critical value in the specimen thickness (t) to grain size (d) ratio divides the strength levels into separate stages on the basis of an increase of the inverse of grain size. In addition, the grain size-dependent fracture morphology is changed in the number of dimples and micro-voids decreasing on the fracture surfaces and the sizes of micro-voids changing larger with the increase of grain size.

Numerical and experimental investigation on the forming behaviour of stainless/carbon steel bimetal composite

2018 ◽  
Vol 101 (1-4) ◽  
pp. 1075-1083 ◽  
Author(s):  
Zhou Li ◽  
Jingwei Zhao ◽  
Fanghui Jia ◽  
Qingfeng Zhang ◽  
Xiaojun Liang ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Carbon Steel ◽  
Bimetal Composite ◽  
Forming Behaviour

Study of multi-objective optimization of process parameters in film posting based on outside mold decoration

2018 ◽  
Vol 50 (7) ◽  
pp. 634-655
Author(s):  
Li Zhigang
Keyword(s):  
Film Thickness ◽  
Radial Basis Functions ◽  
Process Parameters ◽  
Thickness Distribution ◽  
Tensile Tests ◽  
Basis Functions ◽  
Uniaxial Tensile ◽  
Forming Process ◽  
Multi Objective ◽  
Radial Basis

In order to optimize the process parameters in film posting based on outside mold decoration (OMD), the polymethyl methacrylate (PMMA) plastic sheets were tested in uniaxial tensile tests at high temperature with different temperatures and strain rates. The coefficients of the viscoelastic constitutive model called Duan Saigal Greif Zimmerman (DSGZ) were calculated based on the uniaxial tensile tests, and the predicted curve of DSGZ model and experimental data were compared and analyzed. The user material subroutine in ABAQUS of the DSGZ model was designed and written by adopting elastic prediction-radial consumers algorithm and was integrated into ABAQUS for the simulation of forming process of mouse shell posting film using the OMD process. After solving the model, the film thickness distribution and its deforming distribution in the X- and Y-direction were obtained. The optimization objective was to minimize the standard deviation of film thickness and its deforming distribution in the X- and Y-direction for 50 nodes on the thin film of mouse shell. The process parameters of OMD were sampled based on the method of optimal Latin hypercube design. In addition, the radial basis functions model was built. As the analysis shows, the radial basis functions model is sufficiently accurate. Based on the models, the process parameters of OMD were multi-objective optimized and analyzed by adopting archive-based micro-genetic algorithm. The best process parameters group was obtained after comprehensive analysis.

Comparison of two uncoupled ductile damage initiation models applied to DP900 steel sheet under various loading paths

2020 ◽  
Vol 30 (1) ◽  
pp. 25-45
Author(s):  
Zhiyu Tuo ◽  
Zhenming Yue ◽  
Xincun Zhuang ◽  
Xinrui Min ◽  
Houssem Badreddine ◽  
...  
Keyword(s):  
Hot Spot ◽  
Material Model ◽  
Tensile Tests ◽  
Research Field ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Forming Process ◽  
Damage Initiation ◽  
Loading Paths

Accurate prediction of the fracture occurrence of high strength materials is always the hot spot in the research field of metal-forming process. Appropriate material model is the key issue which can accurately describe the mechanical forming behavior under different forming conditions. However, advanced fully coupled damage/behavior models are heavy to use by engineers and have a high cost in term of calculation consuming time. In this paper, a simple uncoupled damage approach, designed to be easy to use for engineers and accurate as well, is investigated. Two uncoupled damage models, which consider the effect of the Lode angle and the hydrostatic pressure, combing three typical hardening rules, are selected and applied to the damage prediction of DP900 dual-phase steel. The hardening properties and forming limit strains under different loading paths of DP900 are investigated and studied throughout a variety of mechanical experiments, including the uniaxial tensile test, the pre-notched tensile tests with three notched radii, and the butterfly tests. Finally, the prediction accuracy of the used models for DP900 is compared and discussed.

scholarly journals Texture Selection Mechanisms during Recrystallization and Grain Growth of a Magnesium-Erbium-Zinc Alloy

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 171
Author(s):  
Fatim-Zahra Mouhib ◽  
Fengyang Sheng ◽  
Ramandeep Mandia ◽  
Risheng Pei ◽  
Sandra Korte-Kerzel ◽  
...  
Keyword(s):  
Grain Growth ◽  
Ternary Alloy ◽  
Solute Drag ◽  
Tensile Tests ◽  
Electron Back Scatter Diffraction ◽  
Zinc Alloy ◽  
Uniaxial Tensile ◽  
Microstructural Stability ◽  
Solid Solution Strengthening ◽  
Zener Drag

Binary and ternary Mg-1%Er/Mg-1%Er-1%Zn alloys were rolled and subsequently subjected to various heat treatments to study texture selection during recrystallization and following grain growth. The results revealed favorable texture alterations in both alloys and the formation of a unique ±40° transvers direction (TD) recrystallization texture in the ternary alloy. While the binary alloy underwent a continuous alteration of its texture and grain size throughout recrystallization and grain growth, the ternary alloy showed a rapid rolling (RD) to transvers direction (TD) texture transition occurring during early stages of recrystallization. Targeted electron back scatter diffraction (EBSD) analysis of the recrystallized fraction unraveled a selective growth behavior of recrystallization nuclei with TD tilted orientations that is likely attributed to solute drag effect on the mobility of specific grain boundaries. Mg-1%Er-1%Zn additionally exhibited a stunning microstructural stability during grain growth annealing. This was attributed to a fine dispersion of dense nanosized particles in the matrix that impeded grain growth by Zener drag. The mechanical properties of both alloys were determined by uniaxial tensile tests combined with EBSD assisted slip trace analysis at 5% tensile strain to investigate non-basal slip behavior. Owing to synergic alloying effects on solid solution strengthening and slip activation, as well as precipitation hardening, the ternary Mg-1%Er-1%Zn alloy demonstrated a remarkable enhancement in the yield strength, strain hardening capability, and failure ductility, compared with the Mg-1%Er alloy.

Comprehensive study on mechanical properties of coated biaxial warp-knitted fabrics

2021 ◽  
pp. 073168442110204
Author(s):  
Bin Yang ◽  
Yingying Shang ◽  
Zeliang Yu ◽  
Minger Wu ◽  
Youji Tao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Least Squares Method ◽  
Tensile Tests ◽  
Tensile Creep ◽  
Base Layer ◽  
Sustained Load ◽  
Uniaxial Tensile ◽  
Membrane Structures ◽  
Knitted Fabrics

In recent years, coated fabrics have become the major material used in membrane structures. Due to the special structure of base layer and mechanical properties, coated biaxial warp-knitted fabrics are increasingly applied in pneumatic structures. In this article, the mechanical properties of coated biaxial warp-knitted fabrics are investigated comprehensively. First, off-axial tensile tests are carried out in seven in-plane directions: 0°, 15°, 30°, 45°, 60°, 75°, and 90°. Based on the stress–strain relationship, tensile strengths are obtained and failure modes are studied. The adaptability of Tsai–Hill criterion is analyzed. Then, the uniaxial tensile creep test is performed under 24-h sustained load and the creep elongation is calculated. Besides, tearing strengths in warp and weft directions are obtained by tearing tests. Finally, the biaxial tensile tests under five different load ratios of 1:1, 2:1, 1:2, 1:0, and 0:1 are carried out, and the elastic constants and Poisson’s ratio are calculated using the least squares method based on linear orthotropic assumption. Moreover, biaxial specimens under four load ratios of 3:1, 1:3, 5:1, and 1:5 are further tensile tested to verify the adaptability of linear orthotropic model. These experimental data offer a deeper and comprehensive understanding of mechanical properties of coated biaxial warp-knitted fabrics and could be conveniently adopted in structural design.

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