# Questions tagged [strength]

This is to be used for topics regarding the strength of materials, the analysis of internal forces in a body and all the governing principles which considers deformation of bodies.

40 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
709 views

### Column Buckling Boundary Conditions -- Welded Tubing Practical Application?

I'm trying to do some calculations for a personal project. I'm trying to understand column strength / buckling. My questions relate to Effective Length Constant, which is based on Boundary ...
• 281
34 views

### Is inverse hall-petch relation valid crystals larger than nanocrystalline?

The image shown here is of ceramics, where they varied the grain size and measured the strength. For example, let's take Al2O3. There we observed that strength first increased from 3 μm to 95 μm. But ...
24 views

### How do I relate Grab Strength and Grab Tear to the real world?

I'm looking at a spec sheet for a high density polyethylene woven fabric and I'm seeing the following parameters on it Tensile Grab Strength: Warp 155 / Weft 170 - tested ASTM D-5034-09 Grab Tear:...
• 121
171 views

### Most efficient fillet design given an envelope (for stress)

If one has a specified allowed X length and Y height, into which a fillet can be placed to reduce stress concentrations, is there an equation which can be used to determine the optimal shape of the ...
• 131
1 vote
14 views

### What is the Hoop stress and bending moment relation

So I am working on a club telescope project. I have to design the tube for the telescope. So I found hoop stress to be most critical stress. The tube's bottommost end has a mirror and a mirror cell. I ...
1 vote
41 views

### Why are these food stretch films (LLDPE) holding one one-thousandth of the weight in reality than what is expected from the datasheet values?

I am trying to reproduce analytically the results found in this experiment where a weight of 3 x 5 lbs (6,8 kgs total) breaks the cling wrap (LLDPE) which is stretched over a medium size cooking pot. ...
1 vote
3k views

### How do I calculate the strength of a carbon fiber tube?

I am not a mech engineer and have been struggling with this for a while, I feel like it is pretty straight forward but I'm missing something. The problem is a horizontal tube that is supported at one ...
1 vote
153 views

### Server rack modifications - strong enough?

Question: Can I modify this rack and have the result still strong enough to hold the content? I have a server rack made from Steel. However it is 1980's old and doesn't quite conform to modern ...
• 430
1 vote
104 views

### Manual vs Fusion360 calculation of natural frequency of beam

I'm trying to uncover the natural frequency of a mass-less beam with 2 masses attached but getting different answers from Fusion360 vs a hand calculation. L1=1m, L2=2m, m1=10kg, m2=20kg, Young's=...
• 11
1 vote
137 views

### How many support beams/rods needed for a firewood storage cabinet

I am building a firewood storage cabinet which should support around 100-150 kg of firewood. The cabinet is made out of wooden boards (...
• 111
1 vote
733 views

### Stopping force exerted on a rope. (Checking if rated strength is sufficient)

I have a 23 kg dog, and a rope lead that is rated to 50 kg. If the dog is running away at say 6 mph and I pull on the lead to decelerate and stop the dog within say half a second or say 0.5 meter what ...
• 11
1 vote
35 views

### Should I use ST or LT values for extruded rod?

In MMPDS for AA7075-73511 (extruded rod) the Table 3.7.10.0(g3) show both ST and LT values for transverse directions. For a rod with circular cross section there is really no Short and Long transverse ...
1 vote
184 views

### Analysis Of Planar Frame Using Hardy Cross Method (Moment Distribution) With Sway

The image shown below is a sketch of the structure/frame that I am attempting to analyse using the Hardy Cross (Moment Distribution) Method. I need to find the bending moments, axial forces and shear ...
• 135
1 vote
500 views

### Will drilling a hole in a pane of glass reduce it's structural integrity?

I've got a glass box that measures 900mm x 450mm x 450mm. The width of the glass is 6mm thick. If I drill, cut, or grind a small hole in/through one of the faces; will it significantly affect the ...
• 201
45 views

### How to calculate the material and thickness I need for a certain force on it?

I am trying to figure out how to design how thick a material has to be so that the bar shown in picture 1 stays intact when a user is running on it. Background: The project is a treadmill and the user ...
20 views

### Techniques to make residential buildings more blast resistant

There are generally two approaches: First: use stronger materials (e.g. thicker RCC with fibres, go underground, etc). Second: for any given material, use a superior design. The First approach is ...
• 123
48 views

### Conflicting steel strength Vs temperature graphs, NIST NCSTAR vs Engineering Toolbox

This graph is from NIST NCSTAR 1-6C And this graph is from the Engineering Toolbox. As you can see, neither the NIST yield or tensile curves match with the ET structural steel curve. Why? And which ...
156 views

### How much weight can aluminum square tube support?

I'm building a bed platform in a campervan and trying to determine what type of aluminum tube to buy. I'm thinking to purchase 6061-T6511 aluminum Square Tube with 1.5" width, 1.5" height ...
• 101
29 views

### Fabricating a Strong Hub Shell for a Bicycle

I'd asked this question over at SE Bicycles but they think this is more an engineering question. The flange on my hub broke and I'm having to get one fabricated. The part is actually a cage that ...
• 101
19 views

### Determine moment and shear stress door

Determine shear stress and moment of bolt: Internal Height of Door = 198.2 cm Internal Width of Door = 89.9 cm Thickness Door = 3.9 cm Weight Door = 45.76 kg or448.9 N Elasticity = 9.8 GPa or N/mm2 ...
12 views

### Is it possible to model the connection of pre-cast and site cast concrete beam on FEA software such as Ansys?

I'm looking for a way to compare the joint strength of beam-to-column connections of pre-cast and site cast concrete. Is it possible to do this on a FEA software?
23 views

### 2" o/d aluminum pipe (1/4" wall) used as 10' 'axle' to 'roll' dock out of water

I'm curious how much weight this 'axle' could support? The dock wheels on ends are capable of 700 lbs each. The dock itself is 10’ wide. The axle will be placed under two 4’ x 2’ rigid black nylon ...
25 views

### What are the change in forces with a ribbon under tension is twisted?

Consider pallet strapping. It has width W. When the strap is flat, it has some maximum breaking strength B. Now, let's put one twist in it over X feet. Mentally we have a VERY skinny isoceles ...
17 views

### Angle of twist at D where 2 shaft connected through gears

So my frind and I find the answer for part A different also chegg says something else. But I can't see whats wrong with my answer. Dont expect you to solve it just show me whats wrong with my answer. ...
• 1
48 views

### Why the size of top and bottom rollers is different in three point bend test?

In a short beam shear testing of polymers, the configuration is such that the top (loading) roller is bigger than the bottom (support) rollers. Why is this the case, and what happens when the size of ...
• 1
23 views

### Is the a similar method of calculating moment in inelastic bending like in the case of torque for inelastic torsion?

When calculating for Torque in torsion or for Moment in the case of bending, the concept is usually first introduced with the simplification of the assumption that the stresses and strains are in the ...
49 views

### 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 ...
953 views

### Timber strength in tangential and radial directions

Normally for structural timber, two values for compressive and tension strength are given. One value is given for timber in direction of the grain, and other is given at 90 degrees (perpendicular) to ...
• 2,259
101 views

• 15
86 views

### Waterlogged multistorey apartment

I fraction invested in a real estate project several years back. Mid way through the construction, after about 12 floors, the building contractor filed for bankruptcy. An asset reconstruction company ...
39 views

### Filler Material

If I was to add a filler to a metallic substance, is it possible for the Young's modulus to decrease as filler content increases? Also, when a filler is added, how do the atoms change for improving ...
226 views

### Is it possible to use Plain Cement Concrete post for fencing?

I am in need of around 700-800 posts to fence my farm in a semi-arid area in TN state, India. In my place granite posts mined from quarries are normally used. It costs around Rs 300-400 per post(6-7ft)...
30 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 ...
297 views

### Best support for a granite table top?: Flat bar 316L Stainless Steel or equal box section or unequal box section

Project is outdoor granite topped table. Table legs are two isosceles trapezoids crossed together at 90 degrees, with the legs having an internal angle of 80 degrees, made from 100 x 100 x 4mm 316L ...
295 views

### How do I calculate the strength to weight ratio of this object?

I have an object that weighs approximately 10 grams = 0.022 pounds. I know it can hold at least 45.1 pounds without breaking. It's a cube-like object so I placed many books on top of it and weighed ...
• 101
49 views

### Thin or thick wall for expanding rubber pressure cylinder

If I want to expand a rubber cylinder by a certain internal volume - with all else held constant (type of material, length and radius (without constraining it), etc.) will a thinner or thicker walled ...
Where does the second moment of area come from and how to derive it from scratch, or what is the basic intuition behind it? In other words, what are the origins of $$I_{xx} = \int\int yy \text{ }dxdy$$...