Necking is a localized deformation process where a material undergoes significant strain in a concentrated area. This concentrated strain can lead to increased stress and strain rates in that region, promoting tertiary creep. As the necking continues, the material undergoes acceleration in deformation until failure occurs.
The displacement is proportional to the strain. This does not factor for creep and time.
Oh, dude, so like, you know how in differential calculus you can find the rate of change of a function, right? Well, in this case, you'd calculate the derivative of the creep strain function with respect to time to get the creep strain rate. It's like finding out how fast your patience is running out while waiting in line at the DMV.
The three factors that affect creep in materials are temperature, applied stress, and time. As temperature increases, materials tend to exhibit higher rates of creep. Similarly, higher applied stress accelerates creep deformation, and longer durations of stress exposure also contribute to increased creep.
The Andrade equation is significant in materials science as it is used to describe the creep behavior of materials. Creep is the gradual deformation of a material under constant stress over time. The Andrade equation helps researchers understand and predict how materials will deform under such conditions. It is a mathematical model that relates the strain rate of a material to the applied stress and temperature, providing valuable insights into the long-term behavior of materials under stress.
Both Fatigue and Creep are causes of failure of a material at a stress value significantly below the Allowable threshold. They differ from each other in the sense that fatigue is defined as the failure of a material, subjected to multiple loading and unloading cycles, even though, in none of the instances, the applied stress crosses the Allowable stress value. The fatigue life of a material is usually specified in # of loading/unloading cycles it can undergo, without failing. The fatigue life decreases as the applied stress approaches the Allowable Stress. CREEP, on the other hand, is time related failure of a material. Creep, explains that a material subjected to a certain applied stress will continue to deform at that constant stress value. Hence, creep results in an increase in strain value while the stress is constant, until it causes the failure of the subject material. CREEP tends to increase with the temperature of the specimen
Creep usually occurs as a result of thermal and physical stress overcoming the elasticity of the metal preventing it from returning to its original shape after the stress is removed.
To calculate the steady state creep rate, you need to measure the change in strain over a specific time period during the creep test. The steady state creep rate, often denoted as (\dot{\varepsilon}{ss}), is determined by taking the slope of the linear portion of the creep curve, which plots strain versus time. Mathematically, it can be expressed as (\dot{\varepsilon}{ss} = \frac{\Delta \varepsilon}{\Delta t}), where (\Delta \varepsilon) is the change in strain and (\Delta t) is the corresponding change in time during the steady state phase. This value is typically expressed in units of strain per unit time, such as per hour or per second.
Tectonic creep, also known as fault creep, refers to the slow, gradual movement of tectonic plates along a fault line without causing an earthquake. It is typically characterized by slow and steady motion, unlike the sudden release of energy associated with earthquakes. This phenomenon helps to relieve stress along fault lines, reducing the likelihood of larger seismic events.
Sharad A. Patel has written: 'Creep behavior of columns' 'Stress distribution in beams of thin-walled sections in the presence of creep' 'Torsion of cylindrical and prismatic bars in the presence of primary creep'
Creep - increase in deformation while load is cst Relaxation - decrease in load while deformation is cst.
A. B Thakker has written: 'Low strain long life creep-fatigue of AF2-1DA and INCO 718' -- subject(s): Materials, Turbines, Creep, Strains and stresses