Measurement of Nonlinear Viscoelastic Properties of Polymers in Cyclic Deformation under a Relatively Large Strain Amplitude

1979 ◽  
pp. 35-52 ◽  
Author(s):  
Y. D. KWON ◽  
R. K. SHARMA ◽  
D. C. PREVORSEK
Keyword(s):  
Strain Amplitude ◽  
Cyclic Deformation ◽  
Viscoelastic Properties ◽  
Large Strain ◽  
Nonlinear Viscoelastic ◽  
Large Strain Amplitude

A novel high-entropy alloy with excellent damping property toward a large strain amplitude environment

2019 ◽  
Vol 802 ◽  
pp. 493-501 ◽  
Author(s):  
Qiang Chen ◽  
Hongling Zhang ◽  
Shuqiang Zhou ◽  
Yuntao Cai ◽  
Xinggang Li ◽  
...  
Keyword(s):  
Strain Amplitude ◽  
Large Strain ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Damping Property ◽  
Large Strain Amplitude

scholarly journals Flat-Cladding Fiber Bragg Grating Sensors for Large Strain Amplitude Fatigue Tests

Sensors ◽  
2010 ◽  
Vol 10 (8) ◽  
pp. 7674-7680 ◽  
Author(s):  
Aihen Feng ◽  
Daolun Chen ◽  
Cheng Li ◽  
Xijia Gu
Keyword(s):  
Fiber Bragg Grating ◽  
Strain Amplitude ◽  
Large Strain ◽  
Fatigue Tests ◽  
Bragg Grating ◽  
Fiber Bragg Grating Sensors ◽  
Large Strain Amplitude

scholarly journals Flat-Cladding Fiber Bragg Grating Sensors for Large Strain Amplitude Fatigue Tests

2021 ◽  
Author(s):  
Aihen Feng ◽  
Daolun Chen ◽  
Cheng Li ◽  
Xijia Gu
Keyword(s):  
Fiber Bragg Grating ◽  
Strain Amplitude ◽  
Large Strain ◽  
Hysteresis Loops ◽  
Cyclic Strain ◽  
Fatigue Tests ◽  
Bragg Grating ◽  
Large Strain Amplitude ◽  
Bragg Grating Sensor ◽  
Cyclic Strain Amplitude

We have successfully developed a flat-cladding fiber Bragg grating sensor for large cyclic strain amplitude tests of up to ±8,000 με. The increased contact area between the flat-cladding fiber and substrate, together with the application of a new bonding process, has significantly increased the bonding strength. In the push-pull fatigue tests of an aluminum alloy, the plastic strain amplitudes measured by three optical fiber sensors differ only by 0.43% at a cyclic strain amplitude of ±7,000 με and 1.9% at a cyclic strain amplitude of ±8,000 με. We also applied the sensor on an extruded magnesium alloy for evaluating the peculiar asymmetric hysteresis loops. The results obtained were in good agreement with those measured from the extensometer, a further validation of the sensor.

scholarly journals Flat-Cladding Fiber Bragg Grating Sensors for Large Strain Amplitude Fatigue Tests

2021 ◽  
Author(s):  
Aihen Feng ◽  
Daolun Chen ◽  
Cheng Li ◽  
Xijia Gu
Keyword(s):  
Fiber Bragg Grating ◽  
Strain Amplitude ◽  
Large Strain ◽  
Hysteresis Loops ◽  
Cyclic Strain ◽  
Fatigue Tests ◽  
Bragg Grating ◽  
Large Strain Amplitude ◽  
Bragg Grating Sensor ◽  
Cyclic Strain Amplitude

We have successfully developed a flat-cladding fiber Bragg grating sensor for large cyclic strain amplitude tests of up to ±8,000 με. The increased contact area between the flat-cladding fiber and substrate, together with the application of a new bonding process, has significantly increased the bonding strength. In the push-pull fatigue tests of an aluminum alloy, the plastic strain amplitudes measured by three optical fiber sensors differ only by 0.43% at a cyclic strain amplitude of ±7,000 με and 1.9% at a cyclic strain amplitude of ±8,000 με. We also applied the sensor on an extruded magnesium alloy for evaluating the peculiar asymmetric hysteresis loops. The results obtained were in good agreement with those measured from the extensometer, a further validation of the sensor.

Viscoelastic Large Strain Model of Bitumen Used for Corrosion Protection in Subsea Cables and Umbilicals

2015 ◽  
Author(s):  
Magnus Komperød ◽  
Bjørn Konradsen ◽  
Roger Slora
Keyword(s):  
Strain Amplitude ◽  
Viscoelastic Properties ◽  
Amplitude Ratio ◽  
Large Strain ◽  
Real Life ◽  
Analytical Models ◽  
Large Strains ◽  
New Instrument ◽  
Strain Model ◽  
Strain Frequency

Bitumen is used as anticorrosion material to protect armor wires in subsea cables and umbilicals. Establishing bitumen’s viscoelastic properties is essential for developing analytical models of how bitumen influences the cable’s mechanical properties, in particular the bending stiffness. A new laboratory instrument has been developed for establishing the viscoelastic properties of bitumen subject to equally large strains as in real-life cables. This paper presents the basic principle of the new instrument and derives how to calculate bitumen’s viscoelastic properties from the measurements logged by the instrument. The paper also models bitumen’s viscoelastic properties as function of strain amplitude, strain frequency, and bitumen temperature, using multi-variable data analysis. These models show that the viscoelastic properties are highly temperature dependent. Bitumen’s shear stress / shear strain amplitude ratio grows with increasing rate as the temperature decreases.

scholarly journals Cyclic Deformation of Semi-solid Processed Magnesium Alloys

2021 ◽  
Author(s):  
Himesh Patel
Keyword(s):  
Fatigue Life ◽  
Magnesium Alloys ◽  
Strain Amplitude ◽  
Cyclic Deformation ◽  
Weight Ratio ◽  
Aging Treatment ◽  
Strain Ratio ◽  
Plastic Strain Amplitude ◽  
Total Strain Amplitude ◽  
Semi Solid

To improve fuel economy and reduce greenhouse gas emissions, magnesium alloys are being considered for automotive and aerospace applications because of their high strength-to-weight ratio. The objective of this thesis was to study monotonic and cyclic deformation behavior of two semi-solid processed (thixomolded) magnesium alloys, AZ91D and AM60B. The fatigue life of these thixomolded alloys was observed to be higher than that of their die cast counterparts. As the total strain amplitude increased, the stress amplitude and plastic strain amplitude increased, while the pseudoelastic modulus decreased. The change in the modulus was attributed to the nonlinear (pseudoelastic) behavior caused by twinning-detwinning during cyclic deformation. The fatigue life increased with decreasing strain ratio, and partial mean stress relaxation occurred mainly in the initial 10-20% of the fatigue life. The fatigue life of theAM60B alloy improved after solution or solution-aging treatment, and the monotonic strength increased by aging, while the thixomolded condition itself exhibited moderate monotonic strength and fatigue life.

scholarly journals Cyclic Deformation Behavior of A Heat-Treated Die-Cast Al-Mg-Si-Based Aluminum Alloy

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4115
Author(s):  
Sohail Mohammed ◽  
Shubham Gupta ◽  
Dejiang Li ◽  
Xiaoqin Zeng ◽  
Daolun Chen
Keyword(s):  
Heat Treatment ◽  
Strain Amplitude ◽  
Cyclic Deformation ◽  
Stress Amplitude ◽  
Cyclic Hardening ◽  
Life Cycles ◽  
Total Strain ◽  
Total Strain Amplitude ◽  
Heat Treated ◽  
Die Cast

The purpose of this investigation was to study the low-cycle fatigue (LCF) behavior of a newly developed high-pressure die-cast (HPDC) Al-5.5Mg-2.5Si-0.6Mn-0.2Fe (AlMgSiMnFe) alloy. The effect of heat-treatment in comparison with its as-cast counterpart was also identified. The layered (α-Al + Mg2Si) eutectic structure plus a small amount of Al8(Fe,Mn)2Si phase in the as-cast condition became an in-situ Mg2Si particulate-reinforced aluminum composite with spherical Mg2Si particles uniformly distributed in the α-Al matrix after heat treatment. Due to the spheroidization of intermetallic phases including both Mg2Si and Al8(Fe,Mn)2Si, the ductility and hardening capacity increased while the yield stress (YS) and ultimate tensile strength (UTS) decreased. Portevin–Le Chatelier effect (or serrated flow) was observed in both tensile stress–strain curves and initial hysteresis loops during cyclic deformation because of dynamic strain aging caused by strong dislocation–precipitate interactions. The alloy exhibited cyclic hardening in both as-cast and heat-treated conditions when the applied total strain amplitude was above 0.4%, below which cyclic stabilization was sustained. The heat-treated alloy displayed a larger plastic strain amplitude and a lower stress amplitude at a given total strain amplitude, demonstrating a superior fatigue resistance in the LCF regime. A simple equation based on the stress amplitude of the first and mid-life cycles ((Δσ/2)first, (Δσ/2)mid) was proposed to characterize the degree of cyclic hardening/softening (D): D=±(Δσ/2)mid − (Δσ/2)first(Δσ/2)first, where the positive sign “+” represents cyclic hardening and the negative sign “−“ reflects cyclic softening.

Sign in / Sign up

Export Citation Format

Share Document