Recent content by Zachary Liu

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    Any physical engine free and open source?

    Hi, I'm trying to simulate the ship traveling in ice. Basically, I would like to assume that the rigid body dynamics is sufficient to do the job since the main point here is the interactions between rigid ice fragments and the rigid ship. The fluid interactions with ice fragments should be...
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    How to Determine Tensile and Compression using 3D Element: Tips and Techniques

    I don't know why you are keeping asking me questions. I'm using more complicate yield function, say Hill yield function, the cap yielding and also the Tsai-wu yield if you know. If you know better, then why not say your solution. thanks!
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    How to Determine Tensile and Compression using 3D Element: Tips and Techniques

    Yes, Studiot. The strength of ice material is highly dependent on the confiment and also strain rate, salinity, granuar size etc.. It is not isotropic in most cases. Anyway, I came to this forum with the hope to find a more efficient way to detect material's failure or damage based on the...
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    How to Determine Tensile and Compression using 3D Element: Tips and Techniques

    Now the discussion is becoming more interesting. Yes, the point or say my intention of the original post is to seek one method to detect the 'failure', the physical mechanics behind. However, I just interpreted as 'tensil' and 'compression' because i also believe that ' material do not fail...
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    How to Determine Tensile and Compression using 3D Element: Tips and Techniques

    I think we are not talking about the DEFINITION, as it could be found in any textbook. The real physical mechanics is of great concerning. I have shown my calculation example in previous post all ready. All the principlal stress \sigma_1,\sigma_2,\sigma_3 are 'negative', so this element...
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    How to Determine Tensile and Compression using 3D Element: Tips and Techniques

    Okay, let's have more discussion. Say we have a typical cylinder triaxial test. The three principal stresses, \sigma_{1},\sigma_2,\sigma_3, are coincidentally the same as \sigma_x,\sigma_y,\sigma_z ( axis z follows the symmetry axis of cylinder). Assuming compression is negative and...
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    How to Determine Tensile and Compression using 3D Element: Tips and Techniques

    No offence at all, but you should know that 'no reply doesn't mean acknowledgment'! I don't think you know much more than me on the Mohr's circle stuff.
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    How to Determine Tensile and Compression using 3D Element: Tips and Techniques

    You might treat this problem too simple. I don't understand what do you mean the 'positive' and 'negative'. Does it mean the relative value of the three principle stress? please specify! As far as I know, the 3D Mohr circle should be obtained after the derivation of 3 principle stress. And...
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    How to Determine Tensile and Compression using 3D Element: Tips and Techniques

    Yes! I'm implementing a new material model on ice, which has different strength on compression and tensil. The stress state is known according to my routine, the question is how to detect the tensil or compression state and invoke damage or fracture mechanics. could tell more about the 3D...
  10. Z

    How to detect the tensil and compression

    Thanks so much. A lot of reading is needed then. As you mentioned the failure criterion, I'm trying to propose a pressure dependent failure criterion to invoke the erosion of elments. I think if a more advanced failure criterion taking into the real stress state of the 3D elments. it will be...
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    How to detect the tensil and compression

    Yes, say I'm working on the geotechnical material modelling with solid elements. I want to simulate both tensil and compression failure. I've dived into several rock and soil books, but I found no answeres yet. Maybe someone here could give me a hint!
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    How to detect the tensil and compression

    Thank you very much for your reply. So you mean the T_d could be used to diagnose the 'tensil' and 'compression' of a 3D stress state? Actually what I'm seeking is a scalar parameter to distinguish the 'tensil' or 'compression' if possible. You know, for some pressure dependent...
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    How to detect the tensil and compression

    what do you mean strain here? remember it is a 3D stress state. So the strain must be 3 dimension. Do you mean volumetric strain, e.g. \epsilon_{v}=\frac{\epsilon_{11}+\epsilon_{22}+\epsilon_{33}}{3} The question is it might be in compression in one direction and tensil in the other. I...
  14. Z

    Finite Element Analysis of Collision Impact in MD Patran/Nastran

    How do you define contact in the simulation?
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    How to Determine Tensile and Compression using 3D Element: Tips and Techniques

    Hi, if I'm using the 3d element, I'm wondering how to detect the tensil and compression for a known stress state? the hydrostatic pressure p has been used before, but i don't think it is correct to all the cases.
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