I'm not at all familiar with phosphoric acid anodizing, but apparently, I'm going to need it as a final process for surface preparations involving adhesive bonding. The problem is that I neither need it nor want it in other areas that do not involve bonding - it obviously involves dipping the...
Have you ever seen someone add static load results to 3Sigma loads? In other words….say I exposed a structure to some aerodynamic and inertial loads and then obtained resulting fastener loads. Then I exposed the same structure to a power spectral density curve and obtained resulting fastener...
I was wondering if someone could give me some free FEMAP tech support as my access to Siemens has lapsed. The question goes like this: I can successfully complete a solve for a laminate structure’s normal modes (#2 Normal Modes/Eigen Value), followed by a solve for the modal frequencies (#4...
I am not well versed in acoustics so bear with me......
I am reading a report that presents an acoustic noise chart whereby a range of 1/3 octave sound pressure vs a frequency range is plotted. The report states a "worst case" value (dB) at a specific frequency and goes on to say that this can...
Something that I've never had a good grasp on was how to determine when I would need a supported or un-supported film adhesive. Is the carrier only used to maintain a consistent bondline thickness? When should one choose a knit vs random carrier?
thanks,
msn
Does anyone know of an acceptable test for evaluating resin properties of a laminate after a cure? I was thinking of probably using ASTM D2344 (short beam, interlaminar shear) but my problem is that the laminate has a cured ply thickness of only .025 inches. This is well below the parameters...
A question for any FEMAP users. My FEM will require a material card for a film adhesive. The properties that I have for the film adhesive are shear modulus, strain at failure and maximum shear stress. What would be the best material card to use for this material?
I would call TECs but it has...
We made a part from ULTEM 9085 using additive manufacturing and then electroplated it with copper. It didn't take long for the darn thing to start corroding. Does anybody know what the heck is happening?
I've been given the enclosed vibration curve. I'm not accustomed to seeing double amplitude vs frequency. Is there a way to convert this to PSD vs frequency?
thanks,
msnhttps://files.engineering.com/getfile.aspx?folder=443f8172-e03b-4989-bb2e-e62d189de10c&file=DA_vs_freq.png
Can someone help me here? I may be having a brain fart. Please take a look at the enclosed figure involving buckling of a panel in pure compression with 4 simply supported sides. How is the enclosed Figure obtained? My plot of the allowable buckling load vs the aspect ratio looks nothing like...
I apologize for this stupid question. I am by no means a whiz at MATLAB like those of you on this thread. I fumble thru it and after using the help documentation, I will usually get things to work out. But this time I am having no luck. I have created a script and it works just fine. It...
I realize that this a pretty broad question - even a little bizarre, but I'll ask it anyway. For the past 15 years or so, I've worked as a strength and structures engineer in the aerospace world. I've become pretty versed in the required skills and techniques but I'm a little curious about...
I am attempting to make some quick predictions for failure of some notched composite specimens using the Whitney-Nuismer point stress or average stress criterion. I have no data (yet). The default values of d0 and a0 are approx d0=.04 inches and a0=.15 inches respectively but I think I can make...
Does anyone know if there has been efforts to look into embedding antenna arrays directly into radome structures? Perhaps there have been technical papers written on the subject. One may ask why would this be done. My answer to this would simply be that compromises in antenna size will reduce...
I am no NDT engineer. I only know enough to cause problems. My question is related to using an eddy current inspection technique to inspect for cracks within a hole. The technique involves using a rotating eddy current probe and the part to be inspected is made from aluminum 2014-T651. We have...
Can anyone provide a recommendation as to where one could send a young engineer to learn the practical use of Strain Gauges? Specifically, we'd like him to learn the proper way to install and use strain gauges in order to obtain material allowables on composite samples, e.g. ASTM D 3039, ASTM D...
Is anyone aware of core shear knockdown factors associated with areas of core that are "peg" spliced together? This method of joining sections of core has always appeared archaic to me - as opposed to using, say, foaming adhesive. Nevertheless, there are still parts out there made this way.
Can anyone recommend a good resource(s) for obtaining elastic and plastic geometry factors in regards to Linear Elastic Fracture Mechanics (LEFM) and Elastic Plastic Fracture Mechanics (EPFM) respectively?
thanks,
Reference Closed thread384-92367
In my quest to calculate Displacement PSD from Acceleration PSD, I've discovered that it's actually quite easy. Nevertheless, would it be correct to say that the units of Displacement PSD are (G^2-sec^4)/Hz ? If that's the case, what is the conversion from that...
reference closed thread384-197452....
My problem is similar to that in the referenced thread. Nevertheless, I have 5 frequencies present. Can I integrate to obtain the Grms and do something similar? For example, my frequencies and PSD values are:
1. 10 Hz, .12 G^2/Hz
2. 25 Hz, .18 G^2/Hz
3. 100...
