Questions tagged [mechanical-failure]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0 votes
2 answers
16 views

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 = ...
user avatar
  • 571
3 votes
2 answers
136 views

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 ...
user avatar
  • 156
1 vote
3 answers
64 views

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 ...
user avatar
2 votes
2 answers
49 views

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! ...
user avatar
3 votes
2 answers
99 views

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 ...
user avatar
0 votes
2 answers
42 views

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 ...
user avatar
0 votes
0 answers
20 views

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 ...
user avatar
1 vote
1 answer
74 views

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, ...
user avatar
3 votes
2 answers
459 views

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 ...
user avatar
0 votes
2 answers
436 views

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!
user avatar
  • 11
1 vote
0 answers
45 views

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,...
user avatar
  • 11
-1 votes
1 answer
261 views

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 ...
user avatar
2 votes
3 answers
1k views

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 ...
user avatar
2 votes
0 answers
31 views

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, ...
user avatar
2 votes
3 answers
433 views

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 ...
user avatar
0 votes
2 answers
113 views

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 ...
user avatar
  • 169
0 votes
2 answers
35 views

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, ...
user avatar
  • 1
0 votes
1 answer
901 views

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 ...
user avatar
0 votes
1 answer
102 views

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 ...
user avatar
  • 101
0 votes
2 answers
92 views

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 ...
user avatar
0 votes
2 answers
408 views

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 ...
user avatar
  • 213
1 vote
1 answer
386 views

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?
user avatar
  • 123
0 votes
3 answers
192 views

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?
user avatar
  • 123
1 vote
2 answers
38 views

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 ...
user avatar
0 votes
0 answers
73 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 ...
user avatar
  • 632
2 votes
4 answers
10k views

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 ...
user avatar
4 votes
1 answer
52 views

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 ...
user avatar
0 votes
0 answers
61 views

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 ...
user avatar
  • 679
2 votes
2 answers
645 views

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 ...
user avatar
3 votes
1 answer
2k views

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 ...
user avatar
1 vote
0 answers
53 views

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?
user avatar
0 votes
1 answer
29 views

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 ...
user avatar
  • 632
3 votes
1 answer
42 views

Behavior of materials on application of tension

Does a test body subjected to a strain that causes plastic deformation still have elastic recovery?
user avatar
  • 131
1 vote
1 answer
687 views

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 ...
user avatar
1 vote
1 answer
72 views

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 ...
user avatar
2 votes
2 answers
15k views

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.
user avatar
  • 123
-2 votes
2 answers
969 views

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.
user avatar
7 votes
4 answers
365 views

Is radians a dimensionless quantity?

Quite often while calculating angular velocity we come across the quantity radians per second. How do I treat radian dimensionally?
user avatar
4 votes
2 answers
8k views

What is Saint Venant Principle?

I am having problem with the application of Saint Venant principle.I have heard that quite often we use that knowingly or unknowingly.I would be very greatful to anyone who would explain this very ...
user avatar
1 vote
2 answers
157 views

Can buckling failure at the first critical load be avoided by "instantaneous" loading?

Previously, I was told by someone I trust well that a column can avoid buckling at the first critical load by applying the load "instantaneously" with a magnitude between the first and second critical ...
user avatar
  • 11
1 vote
1 answer
104 views

How thick of an oxide might form on a cast zinc part?

I'm looking into possible failures of a cast zinc part. I'm wondering if the Zinc-oxide that develops after a time would have a thickness great enough to cause dimensional tolerancing issues? ...
user avatar
  • 632
1 vote
1 answer
109 views

mechanical Strength of 3D printed part

If the material is manufactured by 3D printing (laser sintering) then what will be change in its mechanical properties than the properties by casting and machined part? What would be appropriate ...
user avatar
  • 33
3 votes
3 answers
1k views

Is a gear usually held to a shaft by friction or an adhesive?

So, where I work, we have this arcade game, which is a classic claw machine. IN order to raise the claw up and down the machine makes use of a worm gear, like so: (although for the meticulously ...
user avatar
-1 votes
1 answer
55 views

Can a mechanic pull apart a strong bolt by hand power alone with an ordinary wrench? [closed]

I am wondering whether a typical mechanic can break a bolt using a wrench. For example, let's say the wrench is 15" long and the force is applied at a radius of 13". The mechanic applies a force of ...
user avatar
  • 1,605
4 votes
0 answers
150 views

How to compare small and large scale model of an IC engine to predict force, torque, rpm etc generated by actual engine?

I have this 6 cylinder radial engine designed in Solidworks. Rendering Blueprint (Source:Inventor Wizards) And I want to perform some motion analysis on this engine to make some prediction about it'...
user avatar
  • 41
5 votes
2 answers
5k views

Difference between Precipitation Hardening and Tempered Martensite

The textbook "Materials Science and Engineering An Introduction" mentions that: "Precipitation hardening and the treating of steel to form tempered martensite are totally different phenomena, even ...
user avatar
  • 201
0 votes
2 answers
2k views

Can anyone verify this wall thickness of a pressure cooker?

I am working on designing a pressure cooker. I've have tried to find, using two different models, the wall thickness based on the following assumptions: Cylindrically shaped container Made of ...
user avatar
3 votes
2 answers
3k views

Strength of Welded Joints

When calculating the factor of safety for a fillet weld that is loaded in shear what should be the maximum allowable stress? Some books suggest using the distortion energy (Ssy = 0.577Sy for the ...
user avatar
6 votes
1 answer
3k views

Strength of a Vertical Round Aluminum Tube with load cantilevered off it?

Can a vertical round tube safely support a cantilevered arm mounted near the top of the tube? ROUND VERTICAL TUBE: 6061 Aluminum 2 inch Outside diameter 0.25 inch wall thickness 3 feet height ...
user avatar
  • 63
4 votes
1 answer
91 views

Are Rolling-Element Bearings Practical for Light Loads?

I have a 5" x 4" x 3/8" plastic panel (wall thickness of 1/8", ribbed). I need to slide the panel over a 12" plastic track that is U-shaped (like a skateboard ramp). This motion could be repeated 2 ...
user avatar
  • 419