Questions tagged [mechanical-failure]
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72 questions
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Which of these mechanical properties is the appropriate one to use in Euler's buckling equation?
Here is a datasheet for some carbon fiber rods. A table of mechanical values from the datasheet is given below.
Which value in this table is the correct one to use for $E$ in Euler's buckling formula $...
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Tearing diaphragms on Saunders/Crane 1.5'' EC actuator valve (6 - 8 bar normally closed)
I am having torn diaphragms on my skids (used in pharmaceutical production plant). The tears are coming from 1.5" actuator valves (Saunders/crane EC type actuator normally closed, air to open [6 -...
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How does the thrust rating of a push rod/linear actuator (I've seen it in both kg and N) relate to the amount of weight it can move?
I'm working on a custom RC project, and I'm needing to move a lever with a "weight" of 5 lbs. 5 lbs is required to actuate the lever, and I need to push it 5 mm. Gravity does not affect the ...
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What does it mean for an item's tensile strength to be "rated"?
I found a 40ft. length of rope for sale at the dollar store. Not having high expectations to start with, I examined the packaging closer out of curiosity. The front of the label states that the rope ...
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Impact on high frequency radial forces on ball bearings
Dear Stackexchange forum,
Do high frequency radial forces (e.g. 6kHz) do significantly increase wear and reduce the life span of ball bearings?
I am looking for an expert in ball bearing research ...
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Need help analyzing torque transfer and slippage condition between parts
I have a scenario where Plate A (light blue) shown in the image below is being pressed against two different plates that are in contact with different sections of Plate A. I would like to know which ...
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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 ...
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How do you go about picking a belt in design?
So when you want to pick a beam to use or determining the thickness of a load bearing beam, or picking bearings, there is some calculations you do to see if its life expectancy or f.s or to see if the ...
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Probability of kitchen toaster breaking
does anyone have any data on the probability of a kitchen toaster breaking such as mechanical or electrical faults?
For a school project- teacher put me in charge to find this
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Spherical metal ball contains high pressure superheated steam. If we allow it to cool in atmospheric air, at what pressure steel ball will implode?
Theoretically, I know that steam will start cooling slowly at constant volume to attain thermal equilibrium as per zeroth law of thermodynamics. After some time, steam will condense to water creating ...
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Can the cooling fan in laptop or ceiling fan shaft fail as result of critical speed? But that's not often the case, even if they rotate at high speed
Cooling fan in PC start very fast. Is there any chance of it's failure due to resonance? In opposite, ceiling fan starts very slow, why doesn't it fail by resonance? Does regulator have any ...
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How to align a shaft with gear box and mechanical seal and uc bearing?
I have a 15 inch (381 mm) shaft with 24.95 mm diameter. That shaft is attached with a gearbox (ratio 5:1). The gearbox is driven by a motor (rpm 2750). There is one UC bearing and mechanical seal and ...
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Design Factor and Design Uncertainty Calculation Question
I recently had a discussion about design factors and design uncertainty. Looking in Shigley's Mechanical Engineering Design, pg. 17, ed. 3, there is a detailed discussion of this topic. The authors ...
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Are there disadvantages to using a single multispan beam, vs separate simple beams, for materials that tolerate tension as well as compression?
Suppose the following beam situation within a mundane building (viewed from above). Assume vibration and torsion aren't issues. Suppose we have a choice to span a gap in 2 different ways:
(Grey = ...
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Do yielded columns buckle?
A sufficiently slender column will fail under compression below yield stress by bowing, releasing it's axial elastic strain. This is called buckling. Depending on the slenderness of the column, the ...
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Failure load of hollow tube under transverse compression
How would one analytically calculate the maximum force a tube under transverse compression can withstand? I am specifically looking for a general equation to model the yield strength of a hollow tube ...
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Determining elastic limit for a nonlinearly elastic material, to be used for calculating chord modulus (i.e. Young's modulus) in tensile testing
I have a protein material that is nonlinearly elastic; from the get-go, the stress-strain curve shows quite an immediate curvature.
I have to use chord modulus (reference to ASTM E11-04).
The problem! ...
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What is the reason for forbidding liquids for cooling in drilling on cfrp/Al or cfrp/Ti stacks?
I recently did some research on the effect of cooling on CFRP/Al7075 drilling.But I read somewhere that liquids are forbidden for cooling operations on these multi layer plates !!! , And I wanted to ...
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What is the best time interval in condition monitoring programs for checking rolling bearings?
The time intervals between observing or measuring the vibration of rolling bearings in industrial plants are so important in condition monitoring programs. For instance, some experts measure the ...
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Which will be stronger for securing a cantilever umbrella in a deck
I am securing a cantilever umbrella baseplate to a deck. The decking timber will be reinforced with a pine nog between the deck joists.
The options that I have are to use 10mm stainless steel coach ...
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Specifications of Tensile Test Specimen?
I am Currently Working on Measuring Various Mechanical Properties of Metalic Materials using Universal Testing Machine (UTM) at Various Temperatures. I know that for Testing at Ambient Conditions, ...
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Why is the thin-walled cylinder more likely to experience failure along its axis than along its hoop/circumference?
I was watching a YouTube video to understand the concepts of hoop/circumferential stress and axial/longitudinal stress in thin-walled cylinders and their formula derivation.
So the formula of the ...
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Does a change in specimen dimension affect the measured yield strength and tensile strength?
I am having a hard time trying to understand the effect of geometry on a specimen's yield and tensile strength or if there even is one.
If there is an effect or not, why is it so?
Thanks in advanced!
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Latch design for home exercise equipment [closed]
I have a latch design problem and need your help - many years in software engineering aren't helping me much here!
Two pieces of 60x30mm RHS become parallel/adjacent (on the 60mm face), with a 5mm gap,...
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Length of semi major axis for the ellipse in "Total Strain Energy theory"
The equation describing the "Total Strain Energy Theory" (Haigh & Beltrami's Theory of failure) is given as follows:
$$σ_1 + σ_2 - 2μ σ_1 σ_2 ≤ (Syt)^2$$
where $σ_1$ and $σ_2$ are ...
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Buckling vs. Yielding Failure of Columns
As I have been working through examples of construction projects, I've noticed that in nearly every case of a structural column (sample size considers only homogeneous material columns, no composite ...
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Is a motor failure caused by a defect bearing considered to be a failure mode or is it higher vibration and speed loss in FMEA/FMECA?
Let us assume we have a motor with a bearing which is exhibited to wear. Over time, we can observe higher vibration, increased noise and the motor speed reduces due to the bearing fault. In the end, ...
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DOE analysis or root cause analysis?
For any testing that a part is suppose to pass a test, let's say the leakage test of a seal flange.
How should I individualize the cause?
I know there is root cause analysis and for different ...
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Why does stress act a point instead of on an entire area normal to the stress?
I've often heard stress acts at a point and not on an entire cross-sectional area to which the load is applied normally.
Im a little confused here, Let us consider an area of cross-section ...
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1m3 water container and ice damage prevention
I was looking for data on ice resistance for these kinds of 1000 litres containers. I believe they are made of polyethylene with an outside aluminium structure. Given the physics of ice expansion, ...
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Can crosshead movement be used to measure strain in tensile testing instead of an extensometer?
I am trying to design and build a low cost tensile test machine for plastic specimens. Most machines I've seen measure strain data using an extensometer, either the clamp-on type or the noncontact ...
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compression buckling under lateral load
I'm trying to figure out what size of round tube to use for a tensegrity structure that'll probably have people climbing on it.
The rigid elements are 21' steel tubes, and in normal cases they ...
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Why don't car engine piston-rods (or similar parts) fail as often as other car parts?
Anyone who has owned a car has ultimately dealt with failure of a sensor (parking), or A/C failure, battery shutdown or a tyre puncture. Part breakdowns like these are pretty common, at least ...
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Hollow Steel Tubing: Critical Load for Sidewall Buckling
I'm looking to construct a something with hollow steel tubing (e.g. 10ga 2"x3" rectangular tubing) suspended horizontally welded to an outer frame on both sides.
I've already calculated the ...
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Hardening and Brittleness
Why is hardening and brittle nature so related?What is work hardening or strain hardening as far as true stress strain diagram is concerned?
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Ductile,Brittle and Malleable
In Callister it says, "two modes of failure are possible ductile and brittle." Why not malleable?Furthermore why is uniaxial tensile test chosen for predicting failure?
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Switch at the back of a battery eliminator
I have this variable voltage battery eliminator and the "switch" to hold the wire in place is broken. Is there any specific name for this "switch" and can I buy it somewhere to replace it or can you ...
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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 ...
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What is the difference between tau = VQ/It and tau = V/A?
What is the difference between the formulas $\tau = VQ/It$ and $\tau = V/A$ for finding shear stress due to transverse loading? I understand that the use of first moment of area, is the only reason ...
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How to apply static failure criteria for bending stress in an angled cylindrical surface?
Let’s say I have an irregularly shaped bearing with a cross section that looks like the angled surface of a conical frustum, shown below.
If a bending moment is applied which causes the inside ...
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Plastic failure evaluation of steel using FEM
I would like to evaluate failure in steel using FEM, especially in geometries with stress concentrations (notches etc.).
One possibility is to calculate the stress distribution using a purely linear ...
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How to prevent screw from loosening?
This is a clevis made for linking the tie-rods to the steering rack. This part is under dynamic loading and is getting loosened. We tried using jam nuts but it did not work well. Due to loosening the ...
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Actual amount of reinforcement gained by adding gusset to welded steel tube construction
This question bothers me for quite a while and is about bicycle frame construction, specifically a BMX frame and even more specifically it's front triangle.
It is a heavy duty frame by definition, and ...
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Column Buckling: Which is more useful to plot; Buckling Load vs Slender Ratio, or, Stress vs Slender Ratio [closed]
Both have a linear relationship, is there any merit in plotting one over the other?
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Temperature vs Material Properties - ABS
I'm working on a design that uses fairly large plastic components (ABS, ~400mm longest dimensions). I'm looking at adding a steel component that encapsulates this plastic part. And, the steel part ...
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Behavior of materials on application of tension
Does a test body subjected to a strain that causes plastic deformation still have elastic recovery?
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Coconut Climbing Machine Ideas [closed]
I have been trying to create a machine to climb coconuts as the existing machines are very slow and strenuous to use and frankly, most climbers prefer to climb it manually than use the existing ...
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Historical data for using supervised learning algorithm in the field of Mechanical Engineering [closed]
Being a student in the field of Mechanical Engineering, I am very new to Machine Learning.I did a couple of basic online courses of Machine Learning (including the one by Andrew Ng on Coursera). So, I ...
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Failure in torsion
Why does a ductile rod in torsion fail at an angle perpendicular to its axis? I know the reason for brittle material failing in pure shear but I don't understand the reason for ductile material.
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Moment of force or torque [closed]
Is the moment of force taken in a clockwise and anticlockwise fashion? Why then do we curl our fingers and check it?Explain the equivalence or similarity between the two.
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