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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ANSYS APDL Shape memory effect option of SMA not working

I am trying to define the material properties of a shape memory alloy material in ANSYS APDL V15. There are material properties for Superelastic materials (SUPE option) and material properties for ...
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0answers
256 views

Forcing a part into "home position"

I have a design with two parts (at the moment): a fixed 10cm ring with vertical tracks a freely rotating block with a cut that may freely slide along that tracks: I'm trying to find a low profile ...
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1answer
327 views

Deriving the amplitude of a coulomb (dry friction) damped spring

This is my first time posting anything, but I could not figure out the derivation of the amplitude of the spring for the 4 first oscillations. I am not acquainted with the effect and calculations of ...
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2answers
6k 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 ...
7
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2answers
385 views

On a Diesel/hydraulic DMU train what exactly does the “go faster” lever control?

Let's say that you are driving a Diesel Multiple Unit† with either mechanical* (i.e. an actual gearbox with multiple ratios) or hydraulic (i.e. two or more torque converters) transmission. When you ...
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1answer
116 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....
6
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1answer
310 views

Questions regarding Cornering Stiffness for RC Car

I am a bachelor's level student tasked with modeling the vehicle dynamics of an RC Car that will be made to drive autonomously. I lack prior experience or particularly specific education with vehicle ...
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3answers
186 views

Need some advice, control system animation. Appreciate some help!

I would like to have a 3d simulation of a helicopter landing on a ship. I thought about using matlab for this, as a far as I know you can connect models from Simulink to virtual worlds using blocks, ...
6
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1answer
526 views

What is the equivalent moment of inertia of a two-pivot pendulum?

I am working on a system that consists of a hanging-pendulum thrust balance with two pivot points, one in the front and one in the back There is a heavy weight applied in the front. I can change the ...
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123 views

Schematic Reading - Fluid Control Limit Switch Question

Does limit switch LS1 remain pressed on until the piston moves to LS2?
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0answers
36 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 ...
5
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2answers
217 views

How to analyze a bent beam: Stress concentration?

I am analyzing a beam, that has a bend in it. Intuitively and inspecting FEA results using a linear solver, there is a stress concentration at the bend of this I-beam. The part was not a straight I-...
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1answer
234 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....
5
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3answers
565 views

Buoyancy force problem

I'm trying to design a kind of water valve with inexpensive materials as a first prototype. The water flow from the PVC pipe (1) reach the body of the valve and pass through an aluminum grid (3) to ...
5
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1answer
256 views

Wall functions and separation in turbine blade simulation

I am simulating a turbine and I have some question about standard wall function in FLUENT. Standard wall function requires $y^+$ value between 30 to 60 on the blade. but the following quote states: ...
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0answers
277 views

Explicit Dynamic ANSYS - Origami structure

I am working on a flat-foldable conical structure and I would like to carry out some dynamic tests on it (deployment to get the displacements and accelerations...). I have designed the folded ...
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Effect on pavement by light tracked vehicles with rubber inserts

Is there data available to quantify the effect on pavement by light tracked vehicles with rubber inserts. One example of such a vehicle is the M113 armored personnel carriers shown below.
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4answers
84 views

How can I map a global spherical position of a central normal vector to the rotation of 2 perpendicular motors?

I have a machine that rotates two concentric frames. The outer frame has a motor that rotates it relative to the global y-axis, and the inner frame has a motor that rotates it about the outer frame's ...
4
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0answers
34 views

Why is there limited use of Y (Wye) fittings in a refrigeration system?

I'm a Mechanical Engineering intern currently working in HVAC and Refrigeration for grocery stores. I'm looking into ways, with lower energy losses, to encourage equal flow distribution at liquid pipe ...
4
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1answer
73 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 ...
4
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0answers
75 views

Calculating the bending moment ($M$) of a beam as it relates to stress ($σ$) and strain ($ε$)?

I am trying to learn how to work out the bending moment for progressively complex systems to model a beam. I am assuming only one axis of motion (transverse = $y$). For the basic equations of motion, $...
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0answers
35 views

Soft Material for life indication

I have a mechanism where two parts are screwed and unscrewed and I wish to incorporate a system by which the number of screwing and unscrewing can be indicated. I have thought of a method using the ...
4
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0answers
96 views

Part to pierce the valve on a 16g CO2 cartridge and connect to a Solenoid valve

The specific part that I’m after is something that can connect to a solenoid valve and a CO2 cartridge that will break the seal on the end of the CO2 cartridge. The solenoid valve connection is ...
4
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0answers
75 views

Worm Drive Clutching Mechanism

Problem Description I have a project where I will need to be able to engage and disengage a worm drive (actually two of them). The worm drives are quite small. The worm gear is 49.2mm in diameter ...
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0answers
71 views

Etymology of the term "journal bearing"

Typically the word "journal" refers to a collection of written records, experiences, or transactions. However, there is a common type of bearing known as a sleeve bearing, radial bearing, or journal ...
4
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1answer
106 views

Is an Adjustable Stiffness Flexure Spring possible?

I have recently discovered flexure springs (see image below), and I am interested in using one in an amateur project I am building. However, I would prefer if I am able to adjust the "stiffness" of ...
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0answers
44 views

Efficiency of a planetary gearbox as a function of the lubricants viscosity

So I have a client that is asking about if they should switch from one lubricant to another in a planetary gearbox they have. The main advantage that this new lubricant has is that it has a much ...
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0answers
61 views

Thread identification

I am having a very difficult time identifying this thread. This part is a plug that I am trying to replace because the threads were stripped. The best fit for pitch is 11 threads per inch (imperial), ...
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0answers
853 views

How do you calculate the frictional losses in wire ropes over sheaves?

I am currently pulling a load with a wire rope that is moved through a system of sheaves, but had to replace a smaller wire rope cable (1/2") with a larger wire rope cable (3/4"). The sheave/wire ...
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0answers
51 views

Water wheel Calculations required

Problem: I have been asked to help determine whether a waterwheel is able to generate enough power to run 5 x 15kW pumps in a remote location in Zambia where there is no constant power supply. I work ...
4
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1answer
363 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 ...
4
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0answers
1k views

How to calculate the coupler length in a crank rocker mechanism

I'm trying to learn a bit about building kinematic mechanisms by building a small project. The goal is to be able to open and close a box programmatically via a servo motor. I have a small box that ...
4
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1answer
152 views

In what cases are the roughness values Rt and Ra used?

Roughness measurement instruments output those two values, where Rt is the distance between the top of the highest peak and the bottom of the lowest valley, and Ra is the average distance of every ...
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0answers
90 views

Simplifying head loss across a piping network

I am tasked with designing a compressed air piping network,with and would like to determine the pressure loss across the different layers of instruments -now here is the 3D layout of the network. ...
4
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0answers
66 views

Designing a Safe and Crush-proof Pokemon playing card box using a 3D Super-Elipsoid

My friend has two young Pokemon-addicted sons who carry their 60-card playing decks with them everywhere, typically in a cargo pants pocket. Unfortunately, they have either managed to destroy every ...
4
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2answers
784 views

How Can You Calculate Force to Overcome Friction From an O-Ring Seal?

I essentially have a piston in a tube that is sealed with an O-Ring and actuated with a solenoid. The friction of the O-Ring however, is higher than estimated (guessed as far as I can tell) by the ...
4
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0answers
139 views

What is "Torque Break"?

I am looking at the specifications for thread lockers, and henkel/loctite specify "Torque break" and "Torque prevail" in in./lb. as shown in the link below: http://www.na.henkel-adhesives.com/...
4
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1answer
58 views

Holonomic constraint forces using Lagrange multipliers

Consider a multibody robotic system with Lagrangian $$ L =\frac{1}{2} \dot{q}^{T}M\dot{q} - V $$ and equations of motion of the form $$M(q)\ddot{q}+C(q,\dot{q})\dot{q}+A^{T}(q)\lambda+N(q)=0 $$ where ...
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0answers
2k views

How do I loop through annotations in NX using the NXOpen API in VB?

I'm writing a script to extract all the dimensions from a 2D drawing in NX. In doing so, I have been able to get the dimensions and tolerances on all sheets, along with the zone numbers. This has been ...
3
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1answer
162 views

Modeling rigid body dynamics: Trouble with equations, encountering nonsense answers

Hi, I am working on modeling a simple rigid body dynamic system through a certain range of motion. Here is the picture of the system. I am trying to solve the system for the variables $x_1'', y_1'', ...
3
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4answers
93 views

The behavior of the stress-strain curve of metal, containing a void

Let's assume that in a metal sample without any dislocation, there is a void. Then we conduct a uniaxial tensile test.
3
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0answers
40 views

How does NASA's QueSST X-59 jet work?

The QueSST (Quiet Supersonic Transport) is a project to create a more diffuse sonic boom in order to use supersonic flight commercially without the usual abrupt 1~2 psf pressure spike damaging the ...
3
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0answers
58 views

Glass bottle with a prolonged neck that continues into the inner space

Is it possible to create following two shapes from glass using currently known glass mass production techniques? Shape #1: bottle with a prolonged neck that continues into the inner space, like this (...
3
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0answers
28 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 ...
3
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0answers
41 views

What is the kinetic energy required to impact the surface of asphalt roads?

I am trying to find estimates of the minimum kinetic energy required to impact the surface of asphalt roads as a first-order impact assessment of road functionality to rockfall (i.e. boulders hitting ...
3
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0answers
74 views

Is a Geodesic Dome (fuller dome) that floats possible? What material or engineering effort would it take?

Buckminster Fuller has popularized Geodesic Domes (invented by Dr. Walther Bauersfeld who based it on the use of convex polyhedrons), and thus, making buildings with a very large roofs that don't ...
3
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1answer
123 views

Center of rotation (rigid body)

I know the meaning of (instantaneous) “center of rotation” and “center of zero acceleration” for a rigid body. I know that they do not coincide (in general) and that their positions change with the ...
3
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0answers
86 views

FEA using abaqus, and it does not follow the trend

I am doing finite element analysis of a donut shape for my school work. I'm increasing the thickness of the object with a 1 mm increment and run FEA each time, and then comparing the maximum ...
3
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0answers
22 views

Forces on a wheel during braking (Quarter Vehicle Model)

I have created a simple xcos simulation for quarter wheel using the equations given at the bottom of the image. I understand the total torque on the wheel will be the braking torque and the friction ...
3
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1answer
477 views

Iris mechanism nomenclature - need help to enable better search results

I'm researching iris mechanisms with the goal of building a functioning, weather-sealed door. I am learning much as I go along, but am faced with a challenge in nomenclature (I am not an engineer). I ...

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