# Tag Info

2

You should first identify the purpose of using fiber reinforced concrete (FRC), what it is for, and what it is to improve, then how to achieve the goal. In the attached article, it states: " Fiber-reinforced concrete is used to overcome the difficulty of plain cement concrete which gives very low tensile strength, low ductility strength, and a little ...

1

This is very much platform specific. In general there are many ways of approaching this. A common approach among solvers for unidirectional fiber composite materials (until up to a last decade, because I am a bit rusty on recent developments), is that use 2d elements (see shell elements), and through the thickness they define layers with the orientation of ...

0

In the example you are presenting the shear stresses on cross-section of beam AB are as in the image below. with $\color{green}{green}$ is the shear stress $\tau_v$ which has a single direction (parallel to the shear force) with $\color{red}{red}$ is the torsional stress $\tau_T$, which has a changing direction (see the following graph) if you notice at ...

-1

There are journal articles covering this topic... From previous reading few articles, other than sodium, potassium, magnesium and calcium, lithium is one that worth extracting while strategy of appropriate mining and recovery of lithium is in place.

3

Strain is determined as $\epsilon = (l - l_o)/l_o$. The 0.2% offset strain is the point where $\epsilon = 0.002$. The 0.2% offset stress is determined by using a line that has the same slope as the initial stress strain ... the initial Young's modulus. In materials that are fully elastic up to and beyond this point, the initial slope remains constant. In ...

0

if the material is mild steel then the easiest way to find the yield stress is to plot the stress strain and find the first knee in the curve. if the material does not have a clear yield point, what you do, is you start from 0.2% strain and draw a straight line parallel to the Elastic part of the line (see below). The proof stress 0.2% (equivalent to yield ...

0

Not feasible. Nothing light would be able to support itself. You at least need to be able to withstand wind loading, which at that height will be crazy high. Nothing we have in present day usage. You might be able to build an inflatable that is 50m high, but even that will be a challenge. The only way at present to build such a thing would be a massive ...

1

There is no reasonable way to prevent 'destructive' access to the box by 3rd parties - cardboard is too easily cut, and putting each cardboard box inside a steel box defeats the purpose of cardboard boxes. The best you can achieve is secure them in a taper-resistant way, something that won't allow easy access without "leaving marks" and provides ...

1

The boxes can be strapped using plastic strapping as illustrated It may give you peace of mind but as @Solar_Mike states such straps can be cut and replaced by anyone who has such straps and the tools to apply the straps. If they don't want to replace the straps they can just cut them or cut a hole in the box with any sharp knife. By strapping the boxes all ...

2

You can't lock something that one can gain entry to with any craft knife. While the no-tape box design is novel, taped boxes work well and can be re-used again and again. The tape doesn't ruin it, you just tape over the tape the next time.

0

The biggest issue to having a 'standard' solution is that there are so many different sizes of boxes. If a standard solution is adjustable, then that presents a point of weakness. Since "It's just stiff paper" so if someone wanted to actually protect the contents, they would have to surround the box entirely. That all said, many people have ...

3

You could have a 8mm hole drilled and reamed slightly undersize for a press fit 8mm dowel pin and use a 8mm/8mm swivel clamp which would let you set the angle and height as desired (photo from McMaster).

1

Figure 1. Clamping point. On the webpage you linked it appears that they hold the device on the 8 mm diameter rod sticking out the bottom. (Look at the press-mounted device.) To mount on an aluminium plate and have the back of the instrument in contact with the plate you just need a block of aluminium, steel, plastic, etc., and drill an 8 mm hole 11 mm from ...

11

UPDATED TL;DR: Cast iron has the advantage, because it has a greater capacity to hold heat, and because of its lower conductivity it releases it more slowly, thus its temperature does not fluctuate as much (thus having a more even and steady heat flow) UPDATE: Answering in terms of the advantage (scroll way down) for the following sections Answer to ...

0

I'm a little late to the party here, but it's worth mentioning (if only for anyone that finds this in the future) that IP levels don't stack beyond IPX6. Therefore something that's IP67 doesn't necessarily meet the criteria for water ingress levels 1-6. The same goes for IP68. Another note of worth is that IP67 & IP68 allow for some ingress of water, but ...

6

The Load-Displacement (or Load Extension) and stress strain diagrams are two diagrams identical in shape. See below. The main visible difference is the values on axis (which are at first glance neglected). So, it is natural when you first encounter them to question why do you want to learn about a stress and strain diagram which has obscure quantities (as ...

0

Following the points alephzero made, assuming we have a box with a sturdy geometry, 50 kg divided between the 100 cm of the edge of a square bottom (25cmx25cm) that are hanging from vetical walls of the box is way bellow the ripping resistance of the sandwich cardboard. Of course using good filler material helps a lot, be it old clothes or bubble plastic ...

1

Depending on the design, these folded boxes are good for weights between 60 and 300 pounds. The box is "locked in place" because paper or cardboard can not be stretched. The only way you can easy way to change its shape is to bend it, and you the only way you can bend a piece of paper is to shape it into a cylinder. But you can't "bend" ...

4

You left off a "T" ; it is "time, temperature, transformation". It is a basis to evaluate hardenability of alloy steels. A sample is austenitized, then rapidly cooled to some temperature ,and held at that temperature for a specific time . Then rapidly cooled to room temperature and the microstructure examined . And after one finishes the ...

2

Depends what you mean by "manganese steel". If you mean a low alloy like AISI 1100 types , you are above the curie temperature or you are measuring wrong . If you mean a Hadfield type ( 11 to 14 % Mn) it cooled quickly enough to be mostly retained austenite . It certainly has nothing to do with ferrite stabilizing as that would be magnetic. Because ...

0

If you place your printer on the sides of the shelf as opposed to the middle it will create much less moment, hence much less creeping and deflection. The rack is stiffer 4 times depthwise, you shouldn't need any bracing on the sides. you can use small size cable for bracing the back panel using small cable locks, connectin the four corners of the 2nd and ...

1

According to this reference the second moment of area for the HFS series 2020 and 3030 is respectively (for each beam) $0.74\cdot 10^4 mm^4$ and $1.89\cdot 10^4[ mm^4]$. To give it some perspective the second moment of area you currently have with the MDF (610mm X9mm) is about is about $3.7\cdot 10^4 [mm^4]$. This means that the 3030 will exhibit (on its ...

1

I don't have idea about the material you are mentioning, so no comment there. Instead, I suggest to provide bracings and additional support beams, using shelve angles, as shown below. Also, adding 1/2" - 3/4" plywood board can stiffen the shelve bed. Note, you shall confirm the shelve is rated for your application.

3

First thing first, you need to get hand on the ASME Boiler and Pressure Vessel Code (BPVC Code). Starting division 8, section 1, for safety and quality of your pressure vessel. After checking on all relevant provisions/standards, you can use the equations to derive the required wall thickness for your application. Notation σ_H = hoop stress, psi or MPa D = ...

9

Silicone is not a single substance, it is a very very wide range of different types of materials with widely varying properties! All materials that have several siloxane monomers in them can reasonably be called silicones. This can take almost any shape; foams, glues, coatings, rubbers, oils, powders, gels. 3D printed solids, even. Some silicones will adhere ...

0

That is certainly the hard way to do it. You could go to a local welding supplier and buy or lease a standard steel pressure bottle / tank ; good for probably 3 X your maximum pressure (designed and built in conformance to ASME Sec. 8 , Div.1 ). Stainless steel is certainly not needed for air or most gasses. You don't need a turbine to get the cooling ...

27

There are two reasons why. First, for any glue to stick to something, that something needs to be wettable by the glue. A cured silicone surface is bristling with uncrosslinked silicone units which have extremely low surface energy and hence are very difficult if not impossible to wet by glues like epoxy. This means the cured epoxy exhibits no adhesion to the ...

2

Dislocations travel through a metal crystal while it is being deformed; it is in fact dislocation movement which makes metal crystals yield and deform at loads far below that which you could calculate on the basis of interatomic forces in a perfect lattice. These mobile dislocations tend to pile up against one another and become entangled as the material ...

0

The scaling for a simple case is easy to calculate. Assume a spherical pressure vessel of radius $r$ and wall thickness $t$ with internal pressure $P$. The stress in the walls scales as $$\frac{Pr}{t}.$$ So, if you double $r$, for the same quantity of gas you reduce $P$ by a factor of 8 (since the internal volume scales as $r^3$), which reduces $t$ by a ...

Top 50 recent answers are included