A visco-hyperelastic damage model for cyclic stress-softening, hysteresis and permanent set in rubber using the network alteration theory

2014 ◽  
Vol 54 ◽  
pp. 19-33 ◽  
Author(s):  
G. Ayoub ◽  
F. Zaïri ◽  
M. Naït-Abdelaziz ◽  
J.M. Gloaguen ◽  
G. Kridli
Keyword(s):  
Damage Model ◽  
Cyclic Stress ◽  
Stress Softening ◽  
Permanent Set

Rate Dependent Constitutive Equations of Cyclic Softening

1985 ◽  
Vol 40 (7) ◽  
pp. 653-665
Author(s):  
J. S. Mshana ◽  
A. S. Krausz
Keyword(s):  
Stress Relaxation ◽  
Low Temperature ◽  
Constitutive Equations ◽  
Strain Softening ◽  
Structural Characteristics ◽  
High Stress ◽  
Cyclic Strain ◽  
Cyclic Stress ◽  
Cyclic Softening ◽  
Stress Softening

Constitutive equations of cyclic strain and stress softening for materials with low internal stress levels are derived from the rate theory. The study shows that over the high stress and low temperature range where the description of plastic flow in cyclic softening can be approximated with activation over a single energy barrier, cyclic strain softening is well related to stress relaxation process while cyclic stress softening is related to creep process. The material structural characteristics for cyclic strain softening, cyclic stress softening and stress relaxation are identical. Subsequently, it is shown that cyclic stress and strain softening within the high stress and low temperature range can be evaluated from the constitutive equations using the material structural characteristics measured from a simple stress relaxation test.

scholarly journals Effect of sample preservation on stress softening and permanent set of porcine skin

2015 ◽  
Vol 48 (12) ◽  
pp. 3135-3141 ◽  
Author(s):  
A.S. Caro-Bretelle ◽  
P.N. Gountsop ◽  
P. Ienny ◽  
R. Leger ◽  
S. Corn ◽  
...  
Keyword(s):  
Porcine Skin ◽  
Sample Preservation ◽  
Stress Softening ◽  
Permanent Set

Numerical Fatigue Analysis for Twin Roll Cast Magnesium Sheet Metal Structures

2014 ◽  
Vol 891-892 ◽  
pp. 1021-1026 ◽  
Author(s):  
Johannes Dallmeier ◽  
Otto Huber ◽  
Holger Saage
Keyword(s):  
Sheet Metal ◽  
Damage Model ◽  
Cyclic Stress ◽  
Alloy Sheet ◽  
Stress And Strain ◽  
Load Range ◽  
Sheet Plane ◽  
Cast Magnesium ◽  
Twin Roll Cast ◽  
Twin Roll

In cyclic stress and strain controlled tests, the fatigue life was determined for twin roll cast AM50 magnesium alloy sheet metals. Different stress and strain ratios were applied to cover the technical relevant load range. The investigated sheet metal shows a strong basal texture which leads to twinning in compression parallel to the sheet plane direction. Accordingly, at low cycles to failure Nf the cyclic plastic deformation is dominated by twinning and detwinning. In this study an energy based approach for lifetime estimation is presented and compared with the Smith-Watson-Topper damage model as well as with experimental test results. The energy based approach shows a comparatively high correlation at all investigated stress and strain ratios in a wide cycle range (20< Nf <1.000.000) and is adequate for the lifetime prediction at various mean stresses.

scholarly journals Constitutive modeling of stress softening and permanent set in a porcine skin tissue: Impact of the storage preservation

2016 ◽  
Vol 49 (13) ◽  
pp. 2863-2869 ◽  
Author(s):  
A.S Caro-Bretelle ◽  
P. Ienny ◽  
R. Leger ◽  
S. Corn ◽  
I. Bazin ◽  
...  
Keyword(s):  
Constitutive Modeling ◽  
Skin Tissue ◽  
Porcine Skin ◽  
Stress Softening ◽  
Permanent Set

Stress Softening in Natural Rubber Vulcanizates III. Carbon Black Filled Vulcanizates

1966 ◽  
Vol 39 (5) ◽  
pp. 1544-1552 ◽  
Author(s):  
J. A. C. Harwood ◽  
A. R. Payne
Keyword(s):  
Carbon Black ◽  
Amplification Factor ◽  
Mullins Effect ◽  
Factor X ◽  
Stress Strain ◽  
Stress Softening ◽  
Permanent Set ◽  
Different Types ◽  
Hydrodynamic Effects ◽  
Natural Rubber Vulcanizates

Abstract This paper has confirmed the conclusions of the previous paper that the stress softening (Mullins effect) of a black-loaded vulcanizate is similar in magnitude to the stress softening of a gum rubber if the two vulcanizates are stretched initially to the same stress. The initial stress used in the present work was 180 kg/cm2, which is very near to the breaking stress of these vulcanizates. The similarity of the normalized stress-strain curves for all the vulcanizates, both gum and loaded with 60 phr of different types of black, suggests that the main difference between the stress-strain characteristics of a filled and a pure gum rubber, after the initial stressing cycle, can be accounted for by the strain amplification factor X. The more reinforcing blacks possess the higher X factors, i.e., they stiffen the rubber more than, for example, a fine thermal black. It is concluded that the black is acting mainly in a stiffening capacity due to the hydrodynamic effects of the degenerate carbon black networks. For sulfur crosslinked pure gum vulcanizates, in which the crosslinks are polysulfidic, the stress softening is partly associated with the breakage of polysulfide linkages. These reform in the extended condition and produce a real permanent set, but the major stress softening is attributed to the incomplete recovery of the crosslinked network to its initial random state due to network junctions or similar associations being displaced in a nonaffine way during extension. For example, junctions at the ends of chains which become fully extended at relatively low extensions will be displaced in this way. Thus when the rubber is subsequently strained, the network is already in a preferred disposition.

Inflation of a Thick-Walled Shell Which Exhibits Stress Softening

1998 ◽  
Vol 65 (1) ◽  
pp. 46-50 ◽  
Author(s):  
J. B. Haddow ◽  
J. L. Wegner
Keyword(s):  
Internal Pressure ◽  
Strain Softening ◽  
Complete Removal ◽  
Mullins Effect ◽  
Stress Softening ◽  
Permanent Set ◽  
Virgin State ◽  
Rubberlike Material ◽  
As Stress

The Mullins effect (Mullins, 1947), also known as stress softening, is exhibited by certain rubberlike materials and refers to changes of the mechanical properties, due to prior deformation. Johnson and Beatty (1995) have investigated the Mullins effect in equibiaxial tension by performing cycles of static inflation and deflation experiments on latex balloons. These experiments show that stress softening results in a decrease in the pressure necessary to inflate a balloon, and in addition, indicate inelastic effects of hysteresis and permanent set. The objective of this paper is to investigate the finite deformation static inflation from the virgin state, followed by quasi-static removal of the internal pressure, of a thick-walled homogeneous spherical shell composed of an incompressible isotropic rubberlike material which exhibits stress softening and permanent set. Since the initial inflation of the shell, due to application of an internal pressure, does not result in a homogeneous deformation, a state of residual stress is present after complete removal of the internal pressure. A procedure is presented for the determination of the response of the shell for the first cycle of inflation and deflation from the virgin state, and the analysis includes strain softening and the inelastic effects of hysteresis and permanent set. It is assumed that, for the initial static inflation of the shell from the virgin state, the internal pressure and stress distribution for a monotonically increasing internal or external radius are the same as for a hyperelastic shell, and also that the magnitude of the permanent set of an element of the material is related monotonically to the deformation at the end of the inflation.

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