# Questions tagged [mechanical-engineering]

Questions within the problem domain of mechanical engineering. Mechanical Engineering can be a broad field; consider choosing more specific tags if they apply.

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### Statically determinate system

The exercise is taken from linear algebra and its applications, prof. G. Strang Exercise 2.4.8 Truss I have already found that: m=n=8 → system is statically determinate, therefore solvable by ...
4answers
288 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?
1answer
13 views

### How to find a reference line for “ Form Tolerances”?

In my project I have to choose a form tolerances ( parallelism ) between the handle ( purple part ) and the part that sits inside it ( the grey part ), where the two parts slide on each other. But I ...
1answer
11 views

### Inconsistencies with units for thermodynamic identities

I am working out the temperature for an Ideal diesel cycle: Based on the isentropic properties for an ideal gas. $$T_f = T_i * r^{k-1}$$ Where $T_i = 50 ºF = 510ºR$ If I use ºF, then \$T_f = 172.9ºF = ...
1answer
82 views

### Effect of friction (or horizontal motion) on vertical surface deformation

I am trying to model the dynamics of some system. In summary, the system consists of one horizontal linear actuator that drives an object along a planar surface and one vertical actuator that brings ...
1answer
111 views

### How to calculate the required torque for an azimuth/elevation antenna rotator?

I want to build an antenna rotator for a 1M dish. How do I calculate the required torque for the motor of the elevation axis? Here's a sketch of the problem: If the "bottom" of the dish is the pivot ...
1answer
50 views

### Rotate rack while keeping it engaged with gears

I am trying to design and construct a working replica aircraft instrument (a Horizontal Situation Indicator to be exact) but am facing a couple of issues. The first one can best be demonstrated with ...
1answer
65 views

### how to find the motor specification

I need a motor for my project. My aim is to move a 10 kg mass using a belt pulley system, with a velocity of 15km/hr to a distance of 3.6m. The maximum time for moving the same is 1.5 sec. Can ...
3answers
37 views

### Mechanical Engineering: Pulley Physics and Equivalent In Axial Rotational Gear Machinery

I have looked at pulley physics at this link and this link and this link. Conceptually, is there an equivalent method in physics to do something similarly in axial gear machinery so that the force ...
3answers
65 views

### Countersink bolt vs. Socket Head Cap bolt

I know one advantage of using Contersink bolt is that the surface can be flat as the screw head gets embedded. If I want to join two parts together using bolts. What are the pros and cons of using ...
1answer
118 views

### Instron Test Profile — Failure when steadily dropping the load

I'm working on an Instron 5969 tester, and I'm trying to measure the residual strain in materials within their elastic zone. I'm using the test profile, which allows me to stretch the material a ...
2answers
110 views

### Analysis of Machine Frames With Cut Outs

I have a structure that is used to support two shafts which are carrying relatively high loads. It is composed of two columns and a "shaft supporting block" in the centre (almost acting as a beam). ...
5answers
99 views

### How to choose tolerance size?

I can not really understand how people decide what tolerances to set for a part or assembly. For example: When can I choose 0.2 mm and when 0.002 mm; and if I choose 0.002, why didn't I choose 0.001 ...
1answer
1k views

### How to compare two ANSYS mechanical APDL databases? (.db or .dbb files)

I am new to using ANSYS. I use the student version. Is there a way to find what is the difference between two .db or .dbb files? I have two files say a.db and <...
1answer
320 views

### Quick return mechanism for spring-loaded screw

Looking for a way to convert rotary motion to linear, but it should take less energy to get back to initial position than when going from initial position to the end position. Specifically, a screw ...
1answer
317 views

### Trouble with Base circle and meshing with spur gears

I am a novice who is trying to make some gears. I have followed the formula's but sadly something seems to go wrong and the gear's don't come out right. Below is some dimensions and pictures. Gear 1 ...
3answers
120 views

### Design of Gating & Runner system in Gravity Die Casting

How to design gating and runner system in permanent dies so that material flows smoothly throughout the design without spilling back from the gating channel. What should be the shape of gating system ...
1answer
222 views

### Mechanical vibration of objects

Do you happen to know relevant references in the literature that model the mechanical vibrations of a solid object (preferably antennas) by means of complex representations as a function of time?, i.e....
3answers
3k views

### Deviation of Ideal Rankine Cycle from Actual Rankine Cycle

I'd been having difficulty with a problem from Cengel and Boles, Thermodynamics An engineering approach. The problem is about the deviated Rankine cycle from Idealised ones. The question I would like ...
2answers
37 views

### What can I coat on Stainless sheet (316 L) plate to achieve high thermal reflectivity?

I was thinking of using some Aluminum coating/blanket but the temperatures can reach 550C+ in the Chamber I work at. I am concerned about melting. Let me know. P.S: I am an entry level Engineer. ...
4answers
65 views

### How to calculate beam impact problem

Can anyone help with this Impact problem? It does not seem very difficult but I am having trouble putting all the parts together. Thanks,
1answer
178 views

### Anti-Squat Force Transmission

I’m trying to understand how anti-squat works in motorcycles and how the geometry plays a major role. I don’t understand, however, the reason why the force from the tires that is transmitted to the ...
1answer
60 views

### Lubricant fluid and Rubber compatibility

I have a portable band saw, which I plan to add lubricant fluid to (this is getting ahead of myself, as I haven't even constructed a portable band saw stand). The main problem with this and the reason ...
3answers
38 views

### Linkage between two vertically and horizontally offset wheels

I'm trying to drive a wheel with a radius of 20cm that is 20cm above the motor and horizontally offset by 20cm from the motor, similar to the following: I wonder what a good linkage might be for a ...
1answer
42 views

### Calculating the output torque of a two-input epicyclic gear system

For a simple planetary gear system with a single input shaft of a known torque, the output torques of the other two shaft can be calculated using the equations below (for a steady state system). If I ...
1answer
57 views

### How to reconfigure a control box unit for an SCN5 actuator

An image of the actuator is below. I have a setup that was given to me where there is two configurations, namely 50mm travel and back, and 75mm travel and back to home position. There are two switches ...
2answers
52 views

### Minimum drum wall thickness when rope wrapped around it

I need to design a hollow drum that holds steel wire rope under tension. The wire rope gets pulled from both ends with a force of 200kN, it is wrapped around the drum 5 times. The outer diameter needs ...
0answers
12 views

### How to calculate minimum and maximum cross-section of a compression clip

I am trying to design and 3D a custom snap in fastener, and I am having a hard time figuring out what cross section it needs to have so that it does not break when compressed, but also isn't so that ...
1answer
103 views

### Yield properties of plastic material

What is meant by yield of isotropic plastic material? How is yield of Isotropic plastic material different from the term normal yield which is referred as transition from elastic behaviour to plastic....
2answers
5k views

### How to find press fit/ slip fit for non standard size parts?

I am looking for calculator or chart for slip fit and press fit for non standard size parts. For example, I have oversized dowel pin 10mm +0.03/+0.01 diameter. I need to create a slip fit hole for ...
1answer
84 views

### Wire heating and heat transfer in a cylindrical pattern

I have a series of copper coils with ¼” cooling plates between each coil. The cooling plates will be manufactured from aluminum and cooled using copper tubing. There are seven in series, and a plate ...
1answer
318 views

### Mechanical Advantage of 3 Pulley System

I am a physics teacher, but have found myself teaching engineering. I have come across the following pulley question, and am starting to doubt my own understanding of pulleys ! Until now the rule ...
0answers
22 views

### Three switches executing the same program for SCN5 Actuator

As indicated in How to reconfigure a control box unit for an SCN5 actuator question I want have 4 actuation programs as described below home, 100mm travel, home home, 75mm travel, home home, 50mm ...
2answers
237 views

### mechanics of materials Mohr

I want to know what is the meaning of dσ/du in this solution?
1answer
37 views

### force required to bend .375 thick aluminum tab

We are trying to determine the force that was needed to bend an aluminum tab on a piece of our aircraft equipment. The tab is deflected 2 inches and is 3 inches in length. load was at the tip (3 in ...
1answer
47 views

### Linear Motion Stage with Offset Loading Problem

I'm currently developing a linear motion system which will have to withstand a large offset load (see image below). There will be two rails, each with a carriage on, which will be connected by a beam/...
1answer
87 views

### Break loose torque calculation of lock nut against rotating/acceleating bolts?

I have a Scenario where my lock nut is tightend using a prevailing torque of 14 Nm (as mentioned by the manufacturer) on to the rotor placed between bearings (But the tightening direction and the ...
1answer
87 views

### Alternatives to sawstop technology

Sawstop table saw braking system works by putting a low voltage on the blade, and when it detects that voltage shorted to ground, the blade is retracted and slammed into an aluminum block. The claim ...
2answers
57 views

### How does this AGV rotate without rotating the payload?

How does the AGV carrying payloads of huge heights as compared to it's size turn without turning the payload? Even if the body is attached to a center bearing, the bearing is very smooth then how come ...
1answer
379 views

### How to machine a metal shaft that cannot be turned on a lathe

On a lawn mower there is a non-removeable metal shaft on which a pulley stack sits. The problem is that worn out bushings caused the shaft to wear in two places and this is causing the drive belt for ...
3answers
1k views

### Harvesting thermoelectric energy from computer graphics cards

During CES2015 a well know Graphic Processor Unit (GPU) manufacturer introduced a new GPU. These GPUs need complex thermal management to keep the processor cool. Most GPU accelerator card ...
3answers
128 views

### Are stuffing boxes still relevant?

Three problems: Internal friction due to stuffing materials. - Why does it not matter? If it does then there must be some limits like rpm etc. Not entirely leak proof. - Why are we supposed to keep ...
2answers
47 views

### How to attach a metal rod to an air cylinder?

I have signed up for an engineering class, and the first project is purely mechanical. I've never done mechanical work, so this is quite interesting to me. I have come up with the following project - ...
0answers
17 views

### How to solve stress/strain constitutive equation for system of springs and dampers with a Coulomb friction element added in?

I am attempting to solve the stress/strain constitutive equation for a system of springs, dampers, and a Coulomb friction element. Basic examples for such constitutive equations can be found in this ...
1answer
133 views

### Equivalent Force: Hydraulic rams in H frame machine press

A 100ton H frame machine press can use 1x100 ton ram to exert this amount of force. Can 3x33 ton rams do the same job if they are applied to same area as the 100ton ram? Also in relation to a H ...
1answer
43 views

### horizontal rail to vertical conveyor

I am trying to find a solution at an industrial line problem. I have a product which is cylinder, ~40 grams, 6cm length x 2cm diameter. The products (cylinders) are coming from a machine (output) in a ...
3answers
61 views

### how much force is required to drive a fence post 2ft into soil or sand using a hydraulic press?

I'm building a post driver for the farm and it got me thinking: what force is required to drive a 6ft(1.8 m) 4 inch (100 mm) post 2 ft into the ground? I'm wondering how different soils affect driving ...
2answers
83 views

### Good estimates for torque generated while turning a dial

I'm trying to design a little device which is hand-driven and which involves turning a bevel gear pair. I want a small gear pair but I don't want it to be weak. The forces involved will be small (it's ...
0answers
27 views

### What does a higher eject force do in a clutch?

I am looking at two clutches and the details on both are identical. The only difference is the eject force. One is 3300 and one is 3600. Does a higher eject force mean higher performance? And also ...
1answer
18 views

### How is the sliding velocity between two spiral gears derived?

How is the component of the velocity along the tooth equal to Vsinα for both the meshing gears? Making the relative sliding velocity Vs = V1sinα + V1sinα