Stress relaxation and mechanical behavior of metals

1971 ◽  
Vol 2 (4) ◽  
pp. 1245-1248 ◽  
Author(s):  
D. Lee ◽  
E. W. Hart
Keyword(s):  
Stress Relaxation ◽  
Mechanical Behavior

Analysis of stress relaxation in the nonlinear region of mechanical behavior

2009 ◽  
Vol 51 (5) ◽  
pp. 576-582 ◽  
Author(s):  
A. A. Askadskii ◽  
V. A. Markov ◽  
A. V. Golovanov ◽  
O. V. Pakhneva ◽  
M. N. Popova ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Mechanical Behavior ◽  
Nonlinear Region

Isothermal Stress Relaxation in Al, Alcu and A1vpd Films

1996 ◽  
Vol 436 ◽  
Author(s):  
J. P. Lokker ◽  
J. F. Jongste ◽  
G. C. A. M. Janssen ◽  
S. Radelaar
Keyword(s):  
Stress Relaxation ◽  
Integrated Circuits ◽  
Tensile Stress ◽  
Thermal Cycling ◽  
Mechanical Behavior ◽  
Mechanical Stress ◽  
Plasma Etching ◽  
Isothermal Treatment ◽  
Aluminum Metallization ◽  
Curvature Measurements

AbstractMechanical stress and its relaxation in aluminum metallization in integrated circuits (IC) are a major concern for the reliability of the material. It is known that adding Cu improves the reliability but complicates plasma etching and increases corrosion sensitivity. The mechanical behavior of AlVPd, AlCu and Al blanket films is investigated by wafer curvature measurements. During thermal cycling between 50°C and 400°C the highest tensile stress is found in AlVPd. In a subsequent experiment, the cooling was interrupted at several temperatures to investigate the stress behavior during an eight hour isothermal treatment. Isothermal stress relaxation has been observed in the three types of films and is discussed.

scholarly journals The Mechanical Properties of Rat Tail Tendon

1959 ◽  
Vol 43 (2) ◽  
pp. 265-283 ◽  
Author(s):  
Bernard J. Rigby ◽  
Nishio Hirai ◽  
John D. Spikes ◽  
Henry Eyring
Keyword(s):  
Mechanical Properties ◽  
Simple Model ◽  
Stress Relaxation ◽  
Connective Tissue ◽  
Mechanical Behavior ◽  
Biological Significance ◽  
Connective Tissue Disorders ◽  
Stress Relaxation Behavior ◽  
Tail Tendon ◽  
Rat Tail

The load-strain and stress-relaxation behavior of wet rat tail tendon has been examined with respect to the parameters strain, rate of straining, and temperature. It is found that this mechanical behavior is reproducible after resting the tendon for a few minutes after each extension so long as the strain does not exceed about 4 per cent. If this strain is exceeded, the tendon becomes progressively easier to extend but its length still returns to the original value after each extension. Extensions of over 35 per cent can be reached in this way. Temperature has no effect upon the mechanical behavior over the range 0–37°C. Just above this temperature, important changes take place in the mechanical properties of the tendon which may have biological significance. The application of the techniques used here to studies of connective tissue disorders is suggested. Some of the mechanical properties of tendon have been interpreted with a simple model.

Factors Influencing the Mechanical Behavior of Raw Unfilled Natural Rubber

1984 ◽  
Vol 57 (1) ◽  
pp. 104-117 ◽  
Author(s):  
D. S. Campbell ◽  
K. N. G. Fuller
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber ◽  
Mechanical Behavior ◽  
Relaxation Behavior ◽  
Complete Dissolution ◽  
Factors Influencing ◽  
Stiffening Effect ◽  
Fraction Comparison

Abstract The influence of gel and soluble nonrubbers on the relaxation behavior of raw, bale NR has been studied by testing fractionated and solvent-extracted rubber. The fractionation was carried out by progressive dissolution, each fraction being recovered by evaporation of the solvent. The tests were performed in tension for extensions up to 70%. Removal of the soluble nonrubbers from the bale was found to decrease the rate of stress relaxation quite markedly, especially at longer times. The fractions fell broadly into three categories: sol rubber, “sol + microgel”, and undissolved macrogel. The last, in the case of the more complete dissolution, was an extremely stiff, almost nonrelaxing material. Despite this, the relaxation behavior of the whole bale rubber was closely reproduced by the “sol / microgel” fraction. Comparison of this fraction with the sol rubber showed that the microgel had predominantly a stiffening effect, though it did also significantly reduce the rate of relaxation.

Uniaxial and Biaxial Mechanical Behavior of Human Amnion

2004 ◽  
Vol 844 ◽  
Author(s):  
Michelle L. Oyen ◽  
Triantafyllos Stylianopoulos ◽  
Victor H. Barocas ◽  
Steven E. Calvin ◽  
Robert F. Cook
Keyword(s):  
Energy Dissipation ◽  
Stress Relaxation ◽  
Mechanical Behavior ◽  
Biaxial Tension ◽  
Critical Role ◽  
Material Behavior ◽  
Integral Approach ◽  
Membrane Repair ◽  
Highly Nonlinear

ABSTRACTChorioamnion, the membrane surrounding a fetus during gestation (the “amniotic sac”), is a structural soft tissue for which the mechanical behavior is poorly understood—despite its critical role in maintaining a successful pregnancy and delivery. Preterm rupture of the chorioamnion accounts for one third of all premature births. The structural component of chorioamnion is the amnion sublayer, which provides the membrane's mechanical integrity via a dense collagen network. Amnion uniaxial and planar equi-biaxial tension testing was performed using monotonic loading, cyclic loading and stress-relaxation. The prefailure material behavior was highly nonlinear, exhibiting an approximately quadratic response. Cyclic testing, both uniaxial and biaxial, exhibited dramatic energy dissipation in the first cycle followed by less hysteresis on subsequent cycles and an eventual stable hysteresis response with approximately 20% energy dissipation per cycle. Stress-relaxation testing, both uniaxial and biaxial, demonstrated a load dependent response and continued relaxation after long hold times. A nonlinear viscoelastic (separable) hereditary integral approach was used to model the amnion stress-strain-time response during relaxation. The mechanical results are discussed within the context of the in vivo clinical performance of amnion, and the potential for membrane repair.

scholarly journals Study on the Time-Dependent Mechanical Behavior and Springback of Magnesium Alloy Sheet (AZ31B) in Warm Conditions

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3856
Author(s):  
Jae-Hyeong YU ◽  
Chang-Whan Lee
Keyword(s):  
Magnesium Alloy ◽  
Stress Relaxation ◽  
Dynamic Recrystallization ◽  
Mechanical Behavior ◽  
Alloy Sheet ◽  
Holding Time ◽  
Time Dependent ◽  
Die Set ◽  
Creep And Stress Relaxation ◽  
Springback Angle

In this study, the time-dependent mechanical behavior of the magnesium alloy sheet (AZ31B) was investigated through the creep and stress relaxation tests with respect to the temperature and pre-strain. The microstructure changes during creep and stress relaxation were investigated. As the tensile deformation increased in the material, twinning and dynamic recrystallization occurred, especially after the plastic instability. As a result, AZ31B showed lower resistance to creep and stress relaxation due to dynamic recrystallization. Additionally, time-dependent springback characteristics in the V- and L-bending processes concerning the holding time and different forming conditions were investigated. We analyzed changes of microstructure at each forming temperature and process. The uniaxial tensile creep test was conducted to compare the microstructures in various pre-strain conditions with those at the secondary creep stage. For the bending process, the change of the microstructure after the forming was compared to that with punch holding maintained for 1000 s after forming. Due to recrystallization, with the holding time in the die set of 60 s, the springback angle decreased by nearly 70%. Increased holding time in the die set resulted in a reduced springback angle.

Isothermal Stress Relaxation In Al, AlCu and AlVPd Films

1996 ◽  
Vol 428 ◽  
Author(s):  
J. P. Lokker ◽  
J. F. Jongste ◽  
G. C. A. M. Janssen ◽  
S. Radelaar
Keyword(s):  
Stress Relaxation ◽  
Integrated Circuits ◽  
Tensile Stress ◽  
Thermal Cycling ◽  
Mechanical Behavior ◽  
Mechanical Stress ◽  
Plasma Etching ◽  
Isothermal Treatment ◽  
Aluminum Metallization ◽  
Curvature Measurements

AbstractMechanical stress and its relaxation in aluminum metallization in integrated circuits (IC) are a major concern for the reliability of the material. It is known that adding Cu improves the reliability but complicates plasma etching and increases corrosion sensitivity. The mechanical behavior of AIVPd, AlCu and Al blanket films is investigated by wafer curvature measurements. During thermal cycling between 50°C and 400°C the highest tensile stress is found in AIVPd. In a subsequent experiment, the cooling was interrupted at several temperatures to investigate the stress behavior during an eight hour isothermal treatment. Isothermal stress relaxation has been observed in the three types of films and is discussed.

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