{"id":241270,"date":"2022-11-18T05:06:31","date_gmt":"2022-11-18T05:06:31","guid":{"rendered":"\/forum\/forums\/topic\/questions-about-failure-of-brittle-material\/"},"modified":"2022-11-21T06:28:11","modified_gmt":"2022-11-21T06:28:11","slug":"questions-about-failure-of-brittle-material","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/questions-about-failure-of-brittle-material\/","title":{"rendered":"Questions About Failure Of Brittle Material"},"content":{"rendered":"

Hello, I am trying to analyse a cast iron mould part which squeze between the mold and the hyrolic press during the operation. I prepared model, defined the brittle material as a lineer( Different ultimate tensile and compression), but I am not quite sure about how to evaluate the result correctly, as far as I know I should use mohr coulomb failure tool to define the safety factor and check for the principal stresses. According to that I see no failure in the model also checked in mohr coulomb tool for ultimate tensile and compression however If I wanted to check the von misses stress There is a short edge between two parpenticular parts which has failed(my tensile is 200 mpa the edge has 240 mpa stress). <\/p>\n

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By the way also When I checked the negative principal stress I see -234 Mpa(but my ultimate strenght for compression is 800 Mpa) in the same failed edge in von misses stress. Does it mean my material is failed?<\/p>\n

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Should I be worried about the failure of von misses stress for a ductile material or should I only check for max min principal stress for a failure? As I can see from other topics usally everyone checks for the principal stresses but I could not be sure about it.<\/p>\n

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Also I am seeing values like this, is positive values tensile and negative compression? You can see my model as basicaly below sketch, since I am applying force like that, so I expected to see compression stresses on my part %90 of the part I see positive values. Is that normal?<\/p>\n

Thanks.<\/p>\n

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