# Questions tagged [fatigue]

The tag has no usage guidance.

24 questions
Filter by
Sorted by
Tagged with
31 views

### Difference between failures

I'm studying about the phenomena that enlargement of the pipe entrance due to particle impingements. Our group calls this phenomena as erosion. But it seems to be fatigue failure in mechanical ...
6 views

### Stress Amplitude Calculation in Haigh Diagram beside Limit Line

I want to use the Haigh diagram for mean stress and stress amplitude correction using SODERBERG limit line. All I can find is the relation between stress amplitude and mean stress described at the ...
• 101
1 vote
138 views

### Infinite life of a material, Fatigue Strength

After 10^6 cycles a component is considered to have infinite life. What makes 10^6 cycles a deciding factor for infinite life? Why not 10^8?
35 views

### What does cycle mean in fatigue strength diagram?

A shaft at an usual factory might rotate 2000-3000 (10^3-10^4) per day. So, its rotation cycle easily reaches numbers indicated on X axis below. What does number of cycles in the diagram below exactly ...
• 125
16 views

### Traction loads in cracks - clarification

I need small help with interpretation of traction loads. I cannot find any explanation what does it really mean according to fatigue crack growth. Should I interpret that like any loads applied to ...
25 views

### Costs of fatigue damage - need some statistical data / USA, Europe, Asia

I am looking for (pretty current/actual) statistical data related with Fatigue damage in machines, Annual fatigue costs in industry (for example with refference to Gross Domestic Product), time ...
52 views

### Grain size and fatigue performance correlation for AMS 5662 Inconel 718

I am trying to do a literature review on the correlation between average grain size and fatigue performance of AMS 5662 (solution annealed condition) Inconel 718. The Special Materials Corporation ...
• 249
1 vote
63 views

### Find hotspots in a system

In the image, I have a depicted a system which is undergoing fatigue. Using appropriate solver I have determined the life of each nodes and it is stored in a .csv file. Also I have the connectivity of ...
510 views

### Looking for a compression spring alternative with 10x lifespan

I'm working on a project where 100k spring cycles is gonna last a few months Any recommendations on an alternative? I considered magnets but their sprigabilty isn't great (also, will they get ...
• 115
1 vote
977 views

### Shell vs. solid elements for a fatigue analysis using FEM

What are the advantages and disadvantages of using quads (shells) vs using hexas (solid) in my mesh for a fatigue analysis using a finite element software. Thanks.
1 vote
46 views

### Abaqus vcct fatigue consistently underpredicts disbond growth rate

I'm modelling a fatigue disbond using abaqus. I've understood the disbond growth rate is equal to: $$\dfrac{\partial a}{\partial N} = c_3 \Delta G^{c_4}$$ I've set up an analysis with MMB specimen. I'...
• 69
116 views

### Strength of bolts

I was wondering if it'd be a good idea to attach a 10kg load to the end of a movable steel rod by fastening it with just one M5 bolt. Looking at Misumi's datasheet, M5 (Class 10.9) has an allowable ...
• 351
124 views

### Fatigue modelling in Abaqus

My problem: I'm trying to model fatigue disbond growth in Abaqus. So far I've tried this using multiple approaches with mixed results. What I've tried: I first started with modelling a static general ...
• 69
1 vote
25 views

### Would Amorphous Diamond-like Carbon coatings have a fatigue cycle limit?

I'm aware that polymers like most plastics can go through stress cycles indefinitely as long as the covalent bonds are not ruptured. On the other hand, I hear that even metals like steel and ...
338 views

### Fatigue resistance at filleted corners - Design detail

So, I have a situation where we are putting load on a plate from above, and the plate has a step in it, which was made by milling a bigger block of steel (i.e. there are no layers and everything is ...
• 298
412 views

### Do I use alternating, mean or max/min stresses for Miner's rule?

I am trying to work out fatigue life of a part using Miner's rule, however I am having some trouble working out which stress values to use. I have seen some examples but there seems no rhyme or reason ...
• 275
1 vote
4k views

### Is there any link between tensile strength and endurance limit for steel ?

I'm designing a shaft, and i have to choose a material. I deal with cyclic stress in my machine, so i set up an expression for all the possible stresses and combined it with von Mises criteria for ...
96 views

### Long term deflection

I've been working with a team of 'designers' that are highly concerned over a potential failure mode of ABS plastic. Their theory is that under a static load well under the yield point of the material ...
• 632
210 views

### mean fatigue strength

In context of machine design, what is mean fatigue strength? (as I am thinking I am mixing it up with midrange strength) In my class we deal a lot with steels and this is a low strength steel, but I ...
572 views

### Why do car-seats have an expiration date?

My wife and I are expecting our first child, and therefore are expecting to purchase a car seats. My wife and I have discovered that car seats have "expiration dates": a car seat, no matter how ...
• 296
48 views

### How do I implement scientific experiment to derive a equation called Gerber Line? [closed]

How do I implement scientific experiment to derive a equation relevant to subject of stress and fatigue called Gerber Line equation? May you also provide some historical context to that?
• 203
1 vote
67 views

### stress wave propogation in metals

Over years of flying small airplanes I have seen fatigue cracks and frayed brackets and connections. I wonder if there is an easy way to search the propagation of stress wave in machinery and ...
• 22.1k
3k views

### How does the S-N curve (or Wöhler curve) of a material change with frequency?

How a Material fatigues can be characterized by a Wöhler curve where each datapoint corresponds to a failure with the stress on the y-Axis and the number of cycles on the x-axis. An example is the ...
• 1,618