Dynamic Tensile Characteristics of DP600 Steel Sheets for Automotive Applications

2012 ◽  
Vol 509 ◽  
pp. 40-45
Author(s):  
Dan Yang Dong ◽  
Yang Liu ◽  
Lei Wang ◽  
Chang Sheng Liu
Keyword(s):  
Strain Rate ◽  
Tensile Testing ◽  
High Speed ◽  
Greenhouse Gas Emission ◽  
Testing Machine ◽  
Fracture Mechanisms ◽  
Strain Rates ◽  
Automotive Applications ◽  
Tensile Testing Machine ◽  
Steel Sheets

To reduce fuel consumption and greenhouse gas emission, dual phase (DP) steels have been considered for automotive applications due to their higher tensile strength, better initial work hardening along with larger elongation compared to conventional grade of steels. In such applications, which would create potential safety and reliability issues under dynamic loading, the mechanical behavior of DP steel considering the strain rate must be examined. In the present study, the dynamic tensile behavior of DP600 steel sheets was investigated using a high-speed tensile testing machine at various strain rates. And the quasi-static tensile testing was also conducted on the steel to understand the effect of the strain rate on the tensile property. The fracture mechanisms of the steel were also analyzed. The results show that the mechanical properties of DP600 steel are noticeably influenced by the strain rates. As the strain rate increases, the strength of the steel increases and the obvious yield phenomenon can be observed when the strain rate is above 0.01 s-1. The fracture elongation of DP600 steels decreases with increasing strain rate from 0.001 to 1 s-1, then increases up to the strain rate of 100 s-1 and reaches the lowest value at the strain rate of 1000 s-1. DP600 steel sheet exhibit typical ductile fracture characteristics with dimples morphology of the facture surface when tensile deformed at various strain rates.

Evaluation of the Failure Elongation of Steel Sheets for an Auto-Body at the Intermediate Strain Rate

2008 ◽  
Vol 385-387 ◽  
pp. 749-752 ◽  
Author(s):  
Seok Bong Kim ◽  
Hoon Huh
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Tensile Elongation ◽  
Testing Machine ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Result ◽  
Tensile Testing Machine ◽  
Static State ◽  
Steel Sheets

This paper deals with the dynamic failure elongation of mild steel, SGACD and advanced high strength steel sheets such as TRIP600, DP600 and TWIP steels. The failure elongation has been obtained from the high speed tensile testing machine with various strain rates ranged from 0.003/s to 200/s. The experimental result demonstrates that the tensile elongation does not simply decrease as the strain rate increases, but it decreases from the quasi-static state to the strain rate of 0.1 or 1/s and increases again up to the strain rate of 100/s. Furthermore, some high strength steels have the tendency that the tensile elongation increases as the strain rate increases. Moreover, the localized strain rate hardening in the necking region induces the increase of elongation.

Effect of Coarse-Grained Ring on Mechanical Properties and Cutting Performance of 2011 Aluminum Alloy Extruded Bar

2021 ◽  
Vol 1035 ◽  
pp. 114-118
Author(s):  
Chang Liang Shi ◽  
Yan Ping Niu ◽  
Yi Min Lin ◽  
Quan Hu ◽  
Xin Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Tensile Testing ◽  
High Speed ◽  
Testing Machine ◽  
Eutectic Phase ◽  
Cutting Performance ◽  
Coarse Grained ◽  
Tensile Testing Machine

The effects of coarse-grained ring on the mechanical properties and cutting performance of 2011 aluminum alloy extruded bars were studied by metallographic microscope, scanning electron microscope, tensile testing machine and high-speed lathe. The results show that the microstructure of aluminum alloy extruded bar was composed of α-Al phase, Al7Cu2Fe phase, CuAl2 phase and SnBi eutectic phase. There was a coarse-grained ring in the aluminum alloy extruded bar. The coarse-grained ring reduced the mechanical properties and cutting performance of the aluminum alloy extruded bar. The aluminum alloy extruded bar with a diameter of 30 mm had a coarse-grained ring depth of 9 mm and lower mechanical properties, whose the tensile strength was 287.9 MPa, the elongation was 17%, the cutting performance was poor and the chips were long. The aluminum alloy extruded bar with a diameter of 40 mm had a coarse-grained ring depth of 1 mm, higher mechanical properties and better cutting performance, whose the tensile strength was 394.5 MPa, the elongation was 23.5%, the chips were fine and uniform.

Mechanical behavior of polyimide filament tows under high strain rate tension

2020 ◽  
Vol 32 (7) ◽  
pp. 842-848
Author(s):  
Boyao Wang ◽  
Mengying Zhang ◽  
Enlin Han ◽  
Guofeng Tian ◽  
Guanghua Wang ◽  
...  
Keyword(s):  
Strain Rate ◽  
High Strain ◽  
Testing Machine ◽  
Strain Rates ◽  
Tensile Testing Machine ◽  
Static State ◽  
Elongation At Break ◽  
Split Hopkinson ◽  
Axial Splitting ◽  
Split Hopkinson Tension Bar

The tensile properties of polyimide (PI) filament tows were measured under quasi-static state and at high strain rates with a universal tensile testing machine and a split Hopkinson tension bar, respectively. Experimental results showed that mechanical behaviors of the tows were rather sensitive to strain rate, with failure stress and modulus increasing distinctly but the elongation at break declining as the strain rate increased. Besides, the PI filament tows exhibited a higher growth rate of fracture stress than para-aramid fiber and aramid III fiber did, and scanning electronic microscopy observation on the fracture surface indicated a ductile fracture mode. With the increase of strain rate, the axial splitting of fiber intensified. Further, strength distributions of the PI filament tows were evaluated by a single Weibull distribution function, and the curve predicted was in good accordance with the experimental data obtained.

scholarly journals Erratum to: New tension mechanism for high-speed tensile testing machine

2017 ◽  
Vol 18 (3) ◽  
pp. 561-561
Author(s):  
B. Ruan ◽  
G. Q. Li ◽  
Y. Chen ◽  
P. Mitrouchev ◽  
B. He ◽  
...  
Keyword(s):  
Tensile Testing ◽  
High Speed ◽  
Testing Machine ◽  
Tensile Testing Machine

scholarly journals Dynamic Tensile Behavior of Steel HRB500E Reinforcing Bar at Low, Medium, and High Strain Rates

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 185 ◽  
Author(s):  
Xiang Zeng ◽  
Jingsi Huo ◽  
Haitao Wang ◽  
Zhan Wang ◽  
Mohamed Elchalakani
Keyword(s):  
Strain Rate ◽  
Yield Stress ◽  
High Speed ◽  
Testing Machine ◽  
Dynamic Loads ◽  
Strain Rates ◽  
Stress Strain ◽  
Rc Structures ◽  
Dynamic Increase Factor ◽  
Strain Relationship

The strain rate effect of engineering materials should be considered in the assessment of the performance of reinforced concrete (RC) structures under extreme dynamic loads such as blast and impact. However, the strain rate behavior of 500 MPa-grade anti-earthquake hot-rolled high-strength ribbed bar (HRB500E), used in critical RC members to improve the anti-earthquake performance, has not been investigated and reported in the open literature. That restricts its application in RC structures subjected to extreme dynamic loads. In this paper, dynamic tensile tests of HRB500E steel were conducted using an electromechanical universal testing machine and a servo-hydraulic high-speed testing machine. The stress–strain curves at strain rates ranging from 0.00025 to 550 s−1 were obtained where HRB500E steel was found significantly sensitive to strain rate. Existing formulations to evaluate the dynamic increase factor for yield stress (DIFy) are found to be not suitable for HRB500E steel, thus the widely used Cowper–Symonds and Malvar models for predicting the DIFy were modified based on the test results. Furthermore, the parameter of the Mander material model for describing engineering stress–strain relationship was also calibrated. Finally, the Johnson-Cook and proposed constitutive models for the true stress–strain relationship were examined. The proposed constitutive model can provide better prediction accuracy for yield stress than the Johnson-Cook model.

Comparison of longitudinal elastic properties of proximal and distal strips of aorta-branch junctions from the abdominal aorta of sheep

1983 ◽  
Vol 61 (6) ◽  
pp. 614-618 ◽  
Author(s):  
Janet Cleave ◽  
Margot R. Roach
Keyword(s):  
Strain Rate ◽  
Elastic Properties ◽  
Abdominal Aorta ◽  
Tensile Testing ◽  
Testing Machine ◽  
The Other ◽  
Sectional Area ◽  
Tensile Testing Machine ◽  
Cross Sectional ◽  
Model Studies

Narrow longitudinal continuous strips were cut from the abdominal aorta and its major branches so that each strip contained the same width of aorta, bifurcation, and branch although the lengths of the three segments were different. A grid was marked on each region, and photographs made at a variety of strains as the whole strip was stretched at a strain rate of 2 cm/min with an Instron tensile testing machine. Measurements from the grids gave the strains for each region, and stress–strain curves were calculated. The proximal bifurcation zone was much more extensible than any of the other regions, owing mainly to changes in the "slack" of the collagen fibers (p < 0.01). This would imply that the shape and cross-sectional area of the bifurcation region are apt to change between diastole and systole, and implies that model studies which assume the shape of the bifurcation region is constant may not be accurate.

A study of the rapid deformation behaviour of a range of polymers

1989 ◽  
Vol 328 (1597) ◽  
pp. 1-33 ◽  
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Deformation Behaviour ◽  
Testing Machine ◽  
Polymeric Materials ◽  
High Speed Photography ◽  
Frictional Stress ◽  
Strain Rates ◽  
Petroleum Jelly ◽  
Rapid Deformation

Polymers are increasingly being used in applications where they are rapidly deformed. However, compared with metals, relatively few studies of their mechanical properties at high rates of strain have been published. This paper describes an investigation of the rapid deformation behaviour in compression of a number of widely used polymeric materials. The necessity of properly characterizing polymers is discussed, as the variation of commercial grades bearing the same name is considerable, and furthermore these materials are much more susceptible to change during storage than say metals. The importance of thermal properties to rapid, and hence adiabatic, deformation is pointed out, and tables of such properties are presented. Extensive use was made of high-speed photography (interframe time 7 (is) to study qualitatively the behaviour of solid discs of polymers at strain rates of 2.5 x 10 3 s -1 . The framing speed was sufficiently fast to capture fracture initiation and subsequent failure of all the polymers studied, including polycarbonate (PC), which fails in an almost explosive manner. The darkening of heat-sensitive film in contact with deforming discs was also investigated. Quantitatively, this technique was used to check the applicability of Avitzur’s analysis (Avitzur ( Israel J. Technol . 2, 295-304 (1964)) of a deforming annulus to polymers. Agreement was found to be good and hence friction could be measured during deformation at high rates of strain for the first time. Studies were also carried out to determine the best lubricant for rapid compressive testing. Petroleum jelly was found to reduce the friction closest to zero. An optically identical system was set up in an Instron mechanical testing machine both to perform friction studies and to explore deviation from incompressible behaviour. Agreement with Avitzur’s analysis was found to be poorer, and no lubricant was found to reduce friction below about 3-4 %. PC, with a very high value of frictional stress, showed evidence of a change in volume. Allowances were made for the elastic indentation of the anvils. Higher strain rates were achieved by using an instrumented drop-weight machine and a direct impact Kolsky bar, both developed in this laboratory. Care was taken to eliminate sources of error, including friction and calibration errors. The strain rate sensitivity of the polymers ranged from 5—15 MPa per decade of strain rate. However, most showed some softening as the strain rate was raised from 10 3 to 10 4 s -1 , the exceptions being polybutylene teraphthalate (PBT) and polyvinylidene difluoride (PVDF).

scholarly journals Plasticity and fracture of aluminium 7075 at high strain rates and elevated temperatures

2021 ◽  
Vol 250 ◽  
pp. 05007
Author(s):  
Xueyang Li ◽  
Kedar Pandya ◽  
Nikos Karathanasopoulos ◽  
Christian C. Roth ◽  
Dirk Mohr
Keyword(s):  
Strain Rate ◽  
Elevated Temperatures ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Experimental Program ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Tensile Testing Machine ◽  
Custom Made

Slow, intermediate and high strain rate experiments with UT geometries are performed on aluminum AA7075-T6 sheet metal at various temperatures. The comprehensive experimental program characterizes the plasticity response at temperatures ranging from 20°C to 360°C and at strain rates ranging from 0.001/s to 150/s. The elevated temperature - elevated strain rate experiments are performed on a hydraulic tensile testing machine and a Split Hopkinson Pressure Bar system with a Load Inversion Device along with a custom-made induction heating system. A machine learning based modified Johnson-Cook plasticity model is calibrated to capture the complex strain rate and temperature effect of the observed hardening response.

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