Does something written by a tech support engineer make you subconsciously start checking for misplaced commas? Does my motto “Close enough for highway work!” disqualify me, in your eyes, to talk about something as subtle as the Hall effect? I hope not, because if you bail out now you’ll miss the chance to find out about a completely new electrical material property in ANSYS 14.5, the Hall coefficient RH. It will be supported initially by the EM elements SOLID236 and SOLID237 and eventually by the direct coupled field elements. Continue reading
The nuclear industry and the NRC (Nuclear Regulatory Commission) have made response spectrum their preferred method for analyzing earthquake loading for over 40 years. They provide very clear guidelines for its input and how to combine the modal results, but the intricacies of how to use the combined results in a particular finite element program is by necessity the responsibility of the analyst. That’s one reason why response spectrum is so loved by the technical support engineer. Continue reading
In a previous blog I tried to answer the question, “Should I do a response spectrum?” My answer was basically “No.” That answer was based, in part, on the assumption that the caller didn’t have a response spectrum and would be unlikely to want to create one. A response spectrum is step two of a two-step process in which step one is a transient analysis. Typically, a dynamics specialist creates the response spectrum for the analysts.
Someone called my answer over-simplified and pointed out that creating a response spectrum for a shock loading such as a 20g half sine pulse would be relatively simple to do. Interesting point. Let’s take a deeper dive into this.
As opposed to a seismic response spectrum, which requires a long time-history to be solved, a “shock response spectrum” could be based on a handbook of dynamic load factors for the shape of the shock loading. Damping isn’t too significant in shock response, so it could be conservatively ignored.
If you do technical support long enough you will discover there are only ten questions. Of course there are a myriad of small difficulties, irritations, limitations and complaints that customers call in about, but I’m not talking about those. I’m referring to questions which are almost philosophical in nature. In my area of linear dynamics, one of the ten is, “Should I do a response spectrum analysis?”
What job could be more fun than supporting a general purpose program like ANSYS Mechanical? You get to use ANSYS multiphysics technology and your engineering knowledge to solve many small mysteries, such as: Why doesn’t my model satisfy equilibrium? My solution doesn’t match my hand calculations. You also get to be a coach: How do I model a permanent magnet? One day you’re a stress analyst, the next an amateur scientist. I have to admit I sometimes feel more like Dr. Frankenstein’s assistant than a scientist.