The Parameters of the Stress State in the Operations of Plastic Deformation

2016 ◽  
Vol 684 ◽  
pp. 57-66
Author(s):  
Evgeny N. Sosenushkin ◽  
Vagid A. Kadymov ◽  
Elena A. Yanovskaya ◽  
Andrey A. Tatarencev ◽  
Aleksandr E. Sosenushkin
Keyword(s):  
Plastic Deformation ◽  
Stress State ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Principal Stresses

The invariant characteristics of stress state arising on the sheet metal forming operations are considered. Using the trigonometric presentation of stresses, the stress state is constructed. In this case the trajectories of principal stresses are presented by the help of the arcs of circles, that confirms the nonmonotonicity of the processes of deformation.

Numerical modeling crack propagation of sheet metal forming based on stress state parameters using XFEM method

2013 ◽  
Vol 69 ◽  
pp. 311-326 ◽  
Author(s):  
Fengmei Xue ◽  
Fuguo Li ◽  
Jiang Li ◽  
Min He ◽  
Zhanwei Yuan ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Stress State ◽  
Crack Propagation ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming

PRELIMINARY EXPERIMENTAL/ANALYTICAL CORRELATIONS OF THE FORMING OF STRETCH BROKEN CARBON FIBER TOWS AND LAMINATES

2021 ◽  
Author(s):  
YONI SHCHEMELININ ◽  
RACHEL EISGRUBER ◽  
JARED W. NELSON ◽  
DOUGLAS CAIRNS ◽  
MATT EGLOFF ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Carbon Fiber ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Composite Structures ◽  
Fiber Length ◽  
Materials Testing ◽  
Manufacturing Processes ◽  
Carbon Fiber Composites

Stretch broken carbon fiber (SBCF) is generated by breaking individual filaments in carbon fiber tows at inherent flaws in tension in a continuous process. This process results in randomly broken, collimated fiber fragments. The shorter fiber length improves forming properties while retaining mechanical strength through shear load transfer. SBCF has the potential to take advantage of low-cost manufacturing processes like those used in sheet metal forming, resulting in ordersof- magnitude cost savings and enabling conversion to composite structures across the industry. Because uncured continuous carbon fiber composites do not exhibit significant plastic deformation, they cannot be readily adapted to many common sheet metal forming techniques. SBCF composites exhibit pseudo-plastic deformation, but this deformation is due to different mechanisms. To adapt the manufacturing processes for large and complex parts, new materials testing techniques are needed to quantify the forming behavior of SBCF at the meso-scale (tow and ply). This work’s primary objective is to develop predictive models for complex shape forming and large component characterization. Tests have been developed to characterize the behavior of SBCF tows under various forming conditions. Tow forming and laminate bulge testing allowed for experimental characterization of the SBCF response. Respectively, these tests focus on developing the load-displacement material response along with variation of the strain distribution. Using design of experiment (DOE) technique, the forming response to materials properties such as resin viscosity and mean fiber length have been related. For each test, a correlated Finite Element Analysis (FEA) model was developed, allowing for progression toward understanding a wider array of properties than experimentally.

Prediction of the Volume Fraction of Retained Austenite in Sheet Metal Forming for Trip Steels

2006 ◽  
Author(s):  
Tikun Shan ◽  
Weigang Zhang ◽  
Zhongqin Lin ◽  
Shuhui Li
Keyword(s):  
Stress State ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Stress Triaxiality ◽  
Transformation Rate ◽  
Transformation Kinetics ◽  
Loading Paths

The dependence of the transformation rate on the multiaxial stress state corresponding to different loading paths is investigated. To achieve different loading paths, single shear uniaxial tension, plane strain and equi-biaxial stretching tests have been carried out for BTR380 steel. On Based of the experimental results, the influence of the stress state on stability of retained austenite is analyzed and an equation of transformation kinetics is developed to predict stress triaxiality-dependence strain-induced transformation. In sheet metal forming, the material undergoes complicated deformation. The prediction of the volume fraction of retained austenite during forming process is essential to estimate the contribution of the TRIP effect to improving formability. To this aim, the volume fraction of retained austenite in the part’s different regions has been calculated using the proposed transformation kinetics equation introduced into finite element method. The calculated results were successfully compared with the experimental data measured in deep drawing experiments.

ИССЛЕДОВАНИЕ ТОЧНОСТИ ДЕТАЛЕЙ, ПОЛУЧАЕМЫХ ПРИ РАЗДЕЛИТЕЛЬНЫХ ОПЕРАЦИЯХ В ПЕРЕНАЛАЖИВАЕМЫХ ШТАМПАХ

2018 ◽  
pp. 52-63
Author(s):  
Е. А. Фролов ◽  
В. В. Агарков ◽  
С. И. Кравченко ◽  
С. Г. Ясько
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Balance Method ◽  
Experiment Planning ◽  
Practical Recommendations

To determine the accuracy of the readjustable punches for separating operations (perforation + punching out) of sheet-metal forming, the accuracy parameters were analyzed using the random balance method using the method of experiment planning. Analytical dependencies are obtained to determine the values of deviation of the outer and inner contour dimensions of perforated and punched out sheet parts. From the dependencies obtained, it is possible to estimate and predict the value of deviation in the dimensions of the resulting part at any time during the operation of the punch. Practical recommendations on the calculation of the actuating dimensions of the working elements (stamping punch, matrix) of readjustable punches are offered.

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