# Questions tagged [shock]

The tag has no usage guidance.

22 questions
Filter by
Sorted by
Tagged with
18 views

### What exactly is a Normal shock in a CD Nozzle?

This might sound like a simple straight forward question but it is bothering me for hours now. What exactly is a normal shock in a CD Nozzle?? From various resources I came to know that a normal shock ...
129 views

### How to protect users from shock hazards from electric vehicle high voltage system?

I am in the design phase of an electric vehicle. I have realised that at one point, we will need to implement protective measures to safeguard the users from shock hazards of the high voltage system. ...
1 vote
67 views

### Replicating an impact impulse

I am building a test-rig for a device. I have operational data showing the device experiences impact loads resembling a half-sine pulse with width dt and magnitude F. The test rig's purpose is to ...
1 vote
26 views

### Entropy in Euler equations for compressible flows

In compressible Euler equations, everyone knows the energy equation can be written as $$\dfrac{Ds}{Dt} =0$$ which implies the entropy is constant along the path line. However, we have shockwave as a ...
97 views

### What causes damage to my drone when falling down?

I am trying to design a landing gear system and I am stuck at whether I should use a spring as a kind of shock absorber in my landing gear. Currently, the scope of my project is only concerning about &...
131 views

### Are the modal participation factors bounded for shock response spectrum analysis?

Recently dug myself into the theory of shock response spectrum analysis, but one thing is not clear for me. The theory says that the peak response of the structure can be calculated as the product of ...
388 views

### Shock loading stresses due to falling: what strength to use for acceptance criteria?

We are evaluating a design in which a fall-arresting safeguard would be subject to a shock load in the event of a catastrophic failure of a different component, which is required to meet compliance ...
36 views

### What are the hypersonic Normal shock relationships?

I am learning about hypersonic flow now and there seems to be a lot of discussion about the oblique shock relationships as the Mach tends to be very large. I was wondering what happens to the normal ...
1 vote
40 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 ...
1 vote
58 views

### Half Sine Impulse in a modal Transient Analysis

I have a MDOF FEM model in which I perform a modal transient analysis based on the modal eigenfrequencies extracted in a prior step. I wish to excite only the first natural frequency of the system via ...
1 vote
72 views

### Does the surface roughness play any role in shock absorbing?

Consider a mass of about $130 \pm 10$ kg, falls from height, let say $2.5$ m. In order to dampen the vibration and sound, I use silencer or drop pads. I was wondering if introducing the macroscopic ...
1 vote
150 views

### What height is needed to drop a 72 kg mass to impart a 5000g shock onto a test piece

I am trying to design a simple drop / shock testing machine. We want to rate our products to be shock rated to 5000g. In order to test our products to 5000g I plan on dropping a weight onto the ...
1 vote
38 views

### Can hydraulics be used with a squarish piston?

I'm designing a custom part that needs an active shock absorber and space is restricted. I most likely won't be able to use a stock absorber and was thinking, can two squarish tubes be made tight ...
94 views

### shock absorbing rigid joint

There is this problem I can't figure out. One measurements wheel needs to be attached to a slowly moving but wildly shaking and twitching construction machinery. I am trying to greatly absorb the ...
56 views

### Shock/Isolation mounting under tension

I want to secure a box (roughly 20kg in total) that contains electronic equipment to the underside of a flat steel structure. We can weld onto the underside. The steel structure has a high chance of ...
2k views

### Short circuit in welding

All I know about welding is it is a technique in which electrode is connected to one terminal and the gripper connected to workpiece is in connection with the other terminal. As current passes and ...
1 vote
102 views

### Comparing 2 shock scenarios with different magnitudes and times

For example, How does one compare 100 g's for 6 milliseconds to 45 g's for 11 milliseconds. These are two different shock scenarios with different magnitudes and times, so how can I compare them? If I ...
106 views

### I want a shockproof table for a model train. That is, protection from physical jolts, not electrical volts

I have an N-scale model train (N-scale is about half the size of HO scale). It's so small I could set up an entire layout on something the size of a coffee table. Put a glass top over it and I could ...
1 vote
70 views

### stress wave propogation in metals

Over years of flying small airplanes I have seen fatigue cracks and frayed brackets and connections. I wonder if there is an easy way to search the propagation of stress wave in machinery and ...
3k views

### Are there standard vibration and shock specs for shipment of a product?

Suppose I want to ship my product via UPS, or whatever other professional carrier service. What vibration and shock forces should I design my product to withstand? And how can I effectively test my ...