# All Questions

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15 views

### Using Integral gain for motor positioning

I'm struggling to see how Integral gain is used for motor positioning. Suppose we have an AC motor (with a 2048PPR encoder on the shaft) connected to a winch which drives an object forwards and ...
9 views

### PID controller - negative offset for derivative

I have the microcontroller assembly code for a PID controller and I'm trying to understand how it works. The part that I think is the derivative seems strange to me because it adds a negative offset ...
15 views

### Why is it when taking the moment coefficient relative to c.o.p., the weight is ignored?

I have been working on a question, and my lecturer has hinted me with this equation that doesn't include forces due to weight? $C_{M_x}=C_{M_{ac}}+C_L(x/c−x_{ac}/c)$ What he told us was that due to ...
25 views

### Calculate whether a polycarbonate plate can withstand a certain force

I need to calculate whether a polycarbonate sheet can withstand a certain maximum force. The force is an impact force on any one point of the sheet at any given time. All I have are the Young's ...
14 views

### How to repeat on ABAQUS FEM simulations without reloading the mesh?

I would like to perform several FEM simulations on a given mesh with ABAQUS, where only the orientation of an element set would change in between. Currently, I'm just generating several inp files (...
11 views

### Passivity in State Space Systems

Suppose I have the state space system $a\dot{x} = -x + \frac{1}{k}h(x) + u$, and output $y = h(x)$, where $a,k > 0$. The only information I'm given about $h(x)$ is that $h\in[0,k]$. I want to show ...
32 views

### Why is there a row of circular holes in this concrete beam?

The reinforced concrete beam (approximate dimensions 36" x 18") shown in the image below has a row of circular holes at 3/5ths of the height of the cross-section at approximately 300 mm centres. My ...
10 views

### How does virtual work method relate to matrix method or FEM in structural analysis?

I understand the relationship of force method and displacement method and how we use them in matrices in FEM. How about virtual work? Is it used in matrices and FEM too?
19 views

### Cheap / Easy source of small amount of ferromagnetic metal [closed]

Hello all I have a magnet in my car to stick my phone to the dashboard. But I changed phone and now my new phone needs some metal stuck to the case in order to attract to the magnet. I read online ...
14 views

### Can I use household vacuum cleaner with AquaFilter as construction/industrial one

I'm going to buy Thomas vacuum cleaner with Aqua filter and use it to sand walls a bit with grinder. And after finishing the decoration, use it as an ordinary cleaner. May construction plaster, putty ...
34 views

### Analysis Of Statically Indeterminate Structures By Hand

When double-checking/confirming results produced by structural analysis software, many engineers recommend verifying and spot-checking key or critical members if the entire structure is not analysed. ...
17 views

### 3rd angled orthographic drawings

I have extreme trouble transferring the isometric drawing to 3rd angle orthographic drawings. I also have trouble sketching a view when given 2 views using only projection lines. I was wondering what ...
39 views

### Measuring a pattern size on a flat surface

I want to manually measure the dimension of a pattern printed on a flat surface, with an accuracy of about 0.1mm. For simplicity sake, let's say this is a black rectangle, printed on a white ...
27 views

### Is this function common in PID controllers?

I'm reading some old microcontroller code for a PID algorithm. There's a strange function (to me) that seems to work like this: $output = \frac{1}{n}input + \frac{n-1}{n}previous\_output$ The value \$...
13 views

### Is it possible to edit part inside assembly simultaneously seeing an assembly or some of it?

I would like to design a part, matching other parts of an assembly and I don't want to remember sizes. Can I just restrict editing to some part and/ or create new part from within existing assembly?
8 views

### What is the fundamental subject that we need to start with to understand reacting boundary layer equations in solid rocket propellants?

I came to a pdf on modeling the erosive burn rate of the rocket propellant, what fundamental subjects I need to dive into to understand the "reacting turbulent boundary layer equations"? I have a ...
22 views

### Which method is better to solve indeterminate trusses, force or displacement method?

For statically indeterminate trusses, which method is better? Force or displacement method? And why? I read somewhere that displacement method is not suitable for trusses but I must verify.
59 views

### Calculate deflection of a beam with an arbitrary shape

I have a beam with rectangular cross section, but rather an strange shape in the length wise direction as seen below: So I have taken out the symmetry part of it: And it actually has some nice ...
53 views

### Why is there this perforated pipe inside this vertical construction joint in a reinforced concrete wall?

The picture below shows a veritcal construction joint of an approximately 50 years old reinforced concrete industrial structure. The expansion joint was likely originally sealed with a flexcell which ...
17 views

### From advanced prototype to low-volume production

So to the point. In our project (Robotics project) we mostly use sheet metal and PLA printed parts to build. But we want to level up and be ready for an advanced run and even low-volume production of ...
8 views

### How does slope deflection and energy method relate to matrix methods in indeterminate structural analysis

I want to understand the relationship of slope deflection and energy methods to matrix solutions in indeterminate structural analysis. We can apply force (flexibility) or deflection(stiffness) ...
15 views

### Maximum work from the process

Problem statement: 2 kg of air at 500 kPa expands adiabatically in a closed system until its volume (V) is doubled and it's temperature become equal to that of surrounding which is at 100 kPa, 5°C. ...
10 views

### How to Calculate Work of Finite bar element on distribution load?

Integration equation (2.22) Page 27 on book (page 43 on PDF file on below link). I don't know why it is divided by 2. I think that dividing 2 is not needed. How can understand its reason? L is length ...
33 views

### Why do the sidewalks on USA roads use big, massive stone plates instead of asphalt?

Roads in the USA use asphalt, like every other country. However, the sidewalks don't use asphalt. Instead, they use enormous, gigantic square blocks of some kind of stone material. Where I live, the ...
15 views

### A device to provide real-time proportional resistance to variable force

I'm considering a potential product but I'm not sure about the core technology I'd need. The fundamental idea is that there would be a cable (or something similar) that would be pulled. But as it ...
6 views

### can I scale my part in solidworks using a design table, but without scaling through any sketches?

title says it all.. scaling in solidworks with design tables usually involves providing the table with all the dimensions of the sketch, then producing alternate configurations within the table. is ...
18 views

### Why rotation factor of bearing for inner ring is 1 and for outer ring is 1.2?

V is a rotation factor to account for the difference in ball rotations for outer ring rotation vs. inner ring rotation. V = 1 for inner ring rotation V = 1.2 for outer ring rotation From Shigley's ...
13 views

### How to exit from editing part in place?

I was editing assembly, then selected one part and presses "Edit part in place". How to get out of this mode back to assembly editing?
20 views

### Are there succesful solid fueled internal combustion engines?

Are there any succesful solid fueled internal combustion engines? Particularily, ones that produce shaft power (not rockets and not ramjets)
42 views

### Stability of 3D-printed mask after sterilisation

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6797553/ https://www.hatchbox3d.com/collections/pla We are 3D printing masks that need to be used by medical staff treating COVID19 patients. The first ...
7 views

### Melt plastic powder bed with radiant heat?

I want to melt a bed of plastic powder so that the powder bed once melted and then cooled forms a solid sheet of plastic. In order to melt the powder I'm thinking of passing a nichrome (Ni80/Cr20) ...
23 views

### Solidworks motionstudy/motion study causes parts to “jump”

(solidworks files here) I've made a small assembly thet mooves smoothly manually, but when I try to moove it the same way is motion study, it collides is a strange way... what can be the cause of ...
46 views

### How does 3 “liars” in Strandbeests work?

See video: https://www.youtube.com/watch?v=75Z7-gmd_qk&t=226 This does not make sense to me. As far as I got it, bottom pipe is isolated from top 2 and just controls valve of the top 2 pipes. So, ...
11 views

### Source transfering in converter small-signal ac model

I have encountered this buck boost converter with an input filter. I know how to work this out without the filter but now I find it intimidating to transfer all the components to the output. I am not ...
18 views

### How to measure / calculate Tait-Bryan angles of a moving platform in SimMechanics

I exported a model of the mechanism created in SolidWorks to SimMechanics in order to explore the possibilities of control. To solve the problem, i need to know the angular position of the mobile ...
21 views

### What determines when a road should be widened?

I know this depends on a variety of factors including overall traffic volumes, peak traffic volumes, types of vehicles, and type of road, but how exactly do traffic engineers determine how many lanes ...
57 views

### Low cost molds. Can such molds be produced?

I recently found the following link https://anglingai.com/224b-4-4-blood-line-swim-bait-mold/. There you will see that they sale hundreds of different aluminum molds related to fishing. These molds ...
15 views

### What motor is best for 20kg kart

With the driver the total weight is roughly 80kg. I’m trying to build a drift tricycle and was wondering what sort of motor I should be looking at. I Plan on having a 2:1 ratio to double my torque. ...
5 views

### What's the best type of steam Trap for Superheated Steam?

Process Engineering Newbie here. What kind of Steam Traps are best suited for condensate removal in super-heated steam line or manifold? The super-heated steam is to be supplied to a process reactor ...
11 views

### How to measure and create PVT diagram

We have all seen PVT diagrams. From my understanding one should measure pressure, volume and temperature on or near the outside of the system. Volume: maybe by displacing water initially and then ...
19 views

### Is shock spectrum always obtained for an undamped single degree of freedom system?

I am reading a textbook on fundamentals of vibrations and it has a very brief introduction to shock spectra. It mentions that For comparison purposes, it is customary to use the response of an ...
6 views

### how to automatically add non-specified dimensions to a design table

I would like to create a boss using a spline with many points, then scale it using a design table. The catch is that I don't want to manually set dimensions (in x,y, and z) for each of the points of ...
9 views

### How to repair stripped, leaky pneumatic fitting?

I have a pneumatic cylinder with a stripped fitting, which causes a slow leak. I took it to a machine shop and he tried to re-thread it but there wasn't enough good metal left to get a good thread. He ...
18 views

### Relation between engine size and its power to weight ratio

Is there a relation between engine size and its power to weight ratio? For example if you shrink the engine to half the size will it have exactly half the power?
7 views

### Kent Eisenberg original paper

I am making Kent-Eisenberg simulations, I already have a model though I want to double check against the original paper and not variations of the model. I see a few papers that handle this but the ...
24 views

### What's a simple machine to lift and drop a 100 lbs weight repeatedly using an electric motor?

Essentially I have a 100 lbs. pile driver with an eyelet for lifting it on top. (It's on rails) I want to set up and automated machine to lift and drop the driver at a variable pace. Preferably I ...
15 views

### Switchable engine water pump, is it an improvement?

Some engines nowadays have a switchable water pump that can be turn off at cold start, like the ones found on some Volkswagen diesel engines. There is a mechanical pump that can be disabled at cold ...
23 views

### As a metal forming method, how does a rotary swager work?

Rotary swaging is a cold working process, used to reduce the diameter, produce a taper, or add a point to a round workpiece. This can impart internal shapes in hollow workpieces through the use of a ...