Accurate stress computation in plane strain tensile tests for sheet metal using experimental data

2010 ◽  
Vol 210 (13) ◽  
pp. 1772-1779 ◽  
Author(s):  
Paulo Flores ◽  
Víctor Tuninetti ◽  
Gaëtan Gilles ◽  
Pierre Gonry ◽  
Laurent Duchêne ◽  
...  
Keyword(s):  
Experimental Data ◽  
Plane Strain ◽  
Sheet Metal ◽  
Tensile Tests ◽  
Stress Computation ◽  
Accurate Stress

Drained instability of sand in plane strain

2010 ◽  
Vol 47 (4) ◽  
pp. 400-412 ◽  
Author(s):  
Dariusz Wanatowski ◽  
Jian Chu ◽  
Wai Lay Loke
Keyword(s):  
Experimental Data ◽  
Plane Strain ◽  
Case Studies ◽  
Static Loading ◽  
State Parameter ◽  
Dam Failure ◽  
Triaxial Tests ◽  
Granular Soil ◽  
Laboratory Studies ◽  
Dense Sand

Flowslide or failure of loose granular soil slopes is often explained using liquefaction or instability data obtained from undrained triaxial tests. However, under static loading conditions, the assumption of an undrained condition is not realistic for sand, particularly clean sand. Case studies have indicated that instability of granular soil can occur under essentially drained conditions (e.g., the Wachusett Dam failure in 1907). Laboratory studies on Changi sand by Chu et al. in 2003 have shown that sand can become unstable under completely drained conditions. However, these studies were carried out under axisymmetric conditions and thus, cannot be applied directly to the analysis of slope failures. In this paper, experimental data obtained from plane-strain tests are presented to study the instability behaviour of loose and dense sand under plane-strain conditions. Based on these test data, the conditions for the occurrence of drained instability in plane strain are established. Using the modified state parameter, the conditions for instability under both axisymmetric and plane-strain conditions can be unified. A framework for interpreting the instability conditions of sandy slopes developed under axisymmetric conditions also extends into plane-strain conditions.

Experimental and Numerical Investigations on Hot Deformation Behavior and Processing Maps for ASS 304 and ASS 316

2018 ◽  
Vol 37 (9-10) ◽  
pp. 873-888 ◽  
Author(s):  
Nitin Kotkunde ◽  
Hansoge Nitin Krishnamurthy ◽  
Swadesh Kumar Singh ◽  
Gangadhar Jella
Keyword(s):  
Experimental Data ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Constitutive Models ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Processing Maps ◽  
Hot Deformation Behavior ◽  
Statistical Measures

AbstractA thorough understanding of hot deformation behavior plays a vital role in determining process parameters of hot working processes. Firstly, uniaxial tensile tests have been performed in the temperature ranges of 150 °C–600 °C and strain rate ranges of 0.0001–0.01s−1 for analyzing the deformation behavior of ASS 304 and ASS 316. The phenomenological-based constitutive models namely modified Fields–Backofen (m-FB) and Khan–Huang–Liang (KHL) have been developed. The prediction capability of these models has been verified with experimental data using various statistical measures. Analysis of statistical measures revealed KHL model has good agreement with experimental flow stress data. Through the flow stresses behavior, the processing maps are established and analyzed according to the dynamic materials model (DMM). In the processing map, the variation of the efficiency of the power dissipation is plotted as a function of temperature and strain rate. The processing maps results have been validated with experimental data.

scholarly journals Investigation of diffusion behavior of carburized sheet metal in hot stamping

2019 ◽  
Vol 6 ◽  
pp. 16
Author(s):  
Alexander Horn ◽  
Marion Merklein
Keyword(s):  
Mechanical Properties ◽  
Sheet Metal ◽  
Lightweight Design ◽  
Hot Stamping ◽  
Carbon Diffusion ◽  
Tensile Tests ◽  
Process Window ◽  
Uniaxial Tensile ◽  
Body Parts ◽  
Passenger Safety

Today, manufacturing of structural car body parts faces several challenges, like forming accuracy, passenger safety and lightweight design. One possibility to fulfill these partially rivalling demands is the application of hot stamped components. The combination of hot forming and in-die quenching reduces not only springback, but also results in tensile strengths of more than 1500 MPa. Besides conventional hot stamping, the process can be adapted to manufacture parts with tailored properties. One of the biggest issues of these state-of-the-art processes is the formation of extensive transition zones due to heat transfer. A promising approach to adjust the mechanical properties with a minimized transition zone is tailored carburization of sheet metal. Therefore, the parts are locally coated with graphite, heat treated and subsequently quenched. In this work, the time variant process of carbon diffusion is investigated. Sheets with two different thicknesses are carburized and quenched. The resulting mechanical properties are analyzed using uniaxial tensile tests and microhardness measurements. On this basis, a process window is identified. Furthermore, the applicability of EDX and WDX analysis for the measurement of carbon concentration is investigated within this work.

scholarly journals Considerations for the design of polymeric biodegradable products

2013 ◽  
Vol 33 (4) ◽  
pp. 293-302 ◽  
Author(s):  
André C. Vieira ◽  
Rui M. Guedes ◽  
Volnei Tita
Keyword(s):  
Experimental Data ◽  
Constitutive Models ◽  
Tensile Tests ◽  
Failure Criteria ◽  
Numerical Approach ◽  
Life Cycles ◽  
Strength Failure ◽  
First Order Kinetics ◽  
User Material Subroutine ◽  
Degradation Time

Abstract Several biodegradable polymers are used in many products with short life cycles. The performance of a product is mostly conditioned by the materials selection and dimensioning. Strength, maximum strain and toughness will decrease along its degradation, and it should be enough for the predicted use. Biodegradable plastics can present short-term performances similar to conventional plastics. However, the mechanical behavior of biodegradable materials, along the degradation time, is still an unexplored subject. The maximum strength failure criteria, as a function of degradation time, have traditionally been modeled according to first order kinetics. In this work, hyperelastic constitutive models are discussed. An example of these is shown for a blend composed of poly(L-lactide) acid (PLLA) and polycaprolactone (PCL). A numerical approach using ABAQUS is presented, which can be extended to other 3D geometries. Thus, the material properties of the model proposed are automatically updated in correspondence to the degradation time, by means of a user material subroutine. The parameterization was achieved by fitting the theoretical curves with the experimental data of tensile tests made on a PLLA-PCL blend (90:10) for different degradation times. The results obtained by numerical simulations are compared to experimental data, showing a good correlation between both results.

Evolution of Anand Parameters With Elevated Temperature Aging for SAC Leadfree Alloys

2020 ◽  
Author(s):  
Pradeep Lall ◽  
Vikas Yadav ◽  
Jeff Suhling ◽  
David Locker
Keyword(s):  
Experimental Data ◽  
High Strain ◽  
Constitutive Models ◽  
Tensile Tests ◽  
Model Parameters ◽  
Strain Rates ◽  
Automotive Electronics ◽  
High Strain Rates ◽  
Operating Temperatures ◽  
Electronic Assemblies

Abstract Electronic equipment in automotive, agricultural and avionics applications may be subjected to temperatures in the range of −55 to 200°C during storage, operation and handling in addition to high strain-rates. Strain rates in owing to vibration and shock may range from 1–100 per sec. Temperature in electronic assemblies depends typically on location, energy dissipation and thermal architecture. Some investigators have indicated that the required operating temperature is between −40 to 200°C for automotive electronics located underhood, on engine, on transmission. Prior data indicates the evolution of mechanical properties under extended exposures to high temperatures. However, the constitutive models are often only available for pristine materials only. In this paper, effect of low operating temperatures (−65°C to 0°C) on Anand-model parameters at high strain rates (10–75 per sec) for aged SAC (SAC105 and SAC-Q) solder alloys has been studied. Stress-Strain curves have been obtained at low operating temperatures using tensile tests. The SAC leadfree solder samples were subjected to isothermal-aged up to 4-months at 50°C before testing. Anand Viscoplastic model has been used to describe the material constitutive behavior. Evolution of Anand Model parameters for SAC solder has been investigated. The computed parameters of the experimental data were used to simulate the tensile test and verified the accuracy of the model. A good correlation was found between experimental data and Anand predicted data.

scholarly journals Investigation of diffusion behavior of carburized sheet metal in hot stamping

2018 ◽  
Vol 190 ◽  
pp. 08004 ◽  
Author(s):  
Alexander Horn ◽  
Marion Merklein
Keyword(s):  
Mechanical Properties ◽  
Transition Zone ◽  
Sheet Metal ◽  
Lightweight Design ◽  
Hot Stamping ◽  
Sheet Thickness ◽  
Carbon Diffusion ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Body Parts

Today’s manufacturing of structural car body parts faces several challenges, like forming accuracy and passenger safety. Besides these two requirements, lightweight design plays an important role. One possibility to fulfill these partially rivalling demands is the application of hot stamped parts. The combination of hot forming and in die quenching reduces not only springback, but also results in tensile strengths of up to 1500 MPa. This makes a simultaneous reduction of sheet thickness and therefore weight reduction possible. Further development enabled a tailored adjustment of mechanical properties, for example by applying different cooling conditions along the parts. One of the biggest issues of these state of the art processes is the formation of a transition zone due to heat transfer. A promising approach to adjust the mechanical properties with a minimized transition zone is the carburization of sheet metal. Therefore, the parts are coated with graphite, heat treated and subsequently quenched. In this work, the time variant process of carbon diffusion is investigated. Sheets with two different thicknesses are carburized and quenched. The resulting mechanical properties are analyzed using uniaxial tensile tests and microhardness measurements. The results are correlated with the carbon content measured by EDX-analysis.

Cryogenic Sheet Metal Forming - An Overview

2018 ◽  
Vol 941 ◽  
pp. 1397-1403 ◽  
Author(s):  
Florian Grabner ◽  
Belinda Gruber ◽  
Carina Schlögl ◽  
Christian Chimani
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Tensile Tests ◽  
Al Alloys ◽  
Small Scale ◽  
Improve Energy Efficiency ◽  
Automotive Parts ◽  
Industrial Level ◽  
6Xxx Series

Despite extensive efforts to improve energy efficiency in the automotive sector, the use of light-weight aluminium alloys for car bodies is impeded by formability limitations. Although it is a known phenomenon that Al alloys increase their strength and ductility at very low temperatures, it has not been attempted to exploit this effect to increase their overall formability at an industrial scale. Over the last four years, the cryogenic sheet metal forming behaviour of Al-alloys was extensively investigated to establish a process robust enough for manufacturing automotive parts at an industrial level. Initial experiments include tensile tests at temperatures down to –196 °C for characterisation of 5xxx and 6xxx series Al alloys, providing the mechanical material data for numerical design simulations of sheet metal forming processes at cryogenic temperatures. Numerical simulations will not be discussed in this publication. Furthermore, the necessary hardware for cryogenic sheet metal forming was developed and finally resulted in a semi-automated small scale industrial production site. The production of a miniaturized B-Pillar was demonstrated for 5xxx and 6xxx alloys. Due to the part’s demanding geometry, defect-free deep drawing process is possible at cryogenic temperature only. These results demonstrate that the use of Al alloys could be extended beyond their current applications in cars components. For example, the overall formability of 5xxx series alloys nearly doubles compared to room temperature. This paper shall give an overview over our work in the field of cryogenic aluminium sheet metal forming within the last couple of years.

Plastic flow in extrusion and drawing through conical and wedge-shaped dies: Prediction of central bursting

2006 ◽  
Vol 220 (8) ◽  
pp. 1201-1210 ◽  
Author(s):  
S N Samy ◽  
Ch A R Saleh ◽  
A R Ragab
Keyword(s):  
Experimental Data ◽  
Plane Strain ◽  
Deformation Zone ◽  
Hydrostatic Stress ◽  
Plastic Instability ◽  
Instability Criterion ◽  
Fracture Criteria ◽  
Rigid Plastic ◽  
Stress Criterion ◽  
Plastic Materials

In this article, the plastic flowfields for extrusion and drawing - for rigid plastic materials forced through conical and wedge-shaped dies - are analysed on the basis of Shield's work. A modification to Shield's analysis is developed to account for the redundant deformation. Solutions for axisymmetric and plane strain flows are given. The total forces estimated for both drawing and extrusion operations are compared favourably with available experimental data. On the basis of the present modified Shield's analysis, expressions for the stresses within the die are then derived. These expressions are then employed to predict central bursting by applying two fracture criteria, namely: the hydrostatic stress criterion and the plastic instability criterion. The deformation zone geometry criterion has also been used for comparison. The predictions fairly agree with the experimental results.

Calibration of a Shear Specimen

2016 ◽  
Vol 254 ◽  
pp. 138-143
Author(s):  
Daniel Iosif Maxim ◽  
Liviu Marşavina ◽  
Mircea Cristian Dudescu
Keyword(s):  
Experimental Data ◽  
Sheet Metal ◽  
Shear Test ◽  
Shear Failure ◽  
Pure Shear ◽  
Stress Fields ◽  
Virtual Model ◽  
Shear Tests ◽  
Plastic Model ◽  
Steel Material

Different geometries of shear test specimens were experimentally and numerically investigated. They are used for calibration of a virtual model, to be used for sheet metal blanking. Different specimen configurations were simulated in order to determine the strain and stress fields and the potential of producing pure shear failure. Tensile and shear tests were performed using DC01 steel material. The experimental data are used later to calibrate a material with Johnson-Cook elastic-plastic model.

Sign in / Sign up

Export Citation Format

Share Document