George P Johnson

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About George P Johnson

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  1. Hi, Increasing the time step value will add more mass into the model which will affect the accuracy of the results. As mentioned before the best practice is to have less than 5% added mass (0.05) in the model.
  2. Hi Ram, Increase Gaping to 0.5 and try running the analysis. Keep the inacti to 6. Import the model into HyperCrash and you can check for the penetrations in the solver interfaces. You can depenetrate the nodes automatically over there. Please check the Help Menu on check solver interfaces for HyperCrash also which explains the same.
  3. Hi Ram, For a node, check the characteristics of connected elements. If the node is on the master side or the slave side of an interface, this interface must be verified. The gap of the interface should be verified. Try with slightly increased Gapmin value and also keep Inacti to 6. Meanwhile also check for any penetrations in that interface.
  4. Hi, Mass error happens when the imposed tie step value is much higher. In the engine out file check for the mass error. Best practice is to have less than 5% added mass (0.05).
  5. Hi Bhuvan, Which solver you are using? For OptiStruct, you can model suspension using CELAS element (spring element) and can assign with PELAS or PBUSH property. For RADIOSS, you can model suspension system with Type 4 or Type 13 spring property.
  6. Hi, From the engine out file we can trace what is causing for the time step drop. It can be an element, a node or an interface. •For an element, check the related material (especially its Young modulus and density in case of an elastic-plastic material; and its viscosity in case of a visco-elastic material). There must not be an error in the units system that this data is given in. Check the size of the element, since elemental length is proportional to time step. •For a node, check the characteristics of connected elements. If the node is on the master side or the slave side of an interface, this interface must be verified. •For an interface, the gap of the interface must be verified if some failure happens on the master or the slave side of the interface. Once this is cleared you can run the simulation without time step being dropped. Please watch this webinar which explains about time step control: http://www.altairuniversity.com/learning-library/considerations-about-time-step/
  7. Hi Narasimhamurthy, I just recreated the Type 2 interface and updated the load. Please try with the model attached. model.zip
  8. Hi Sandeep, Please go through this document http://www.altairuniversity.com/wp-content/uploads/2013/05/HTC2012_Midsurfacing_Training.pdf which explains about Advanced Midsurfacing options. And meanwhile please go through HM-2015: Auto-Midsurfacing with Advanced Extraction Options tutorial also which shows advanced options for midsurfacing.
  9. Hi Narasimhamurthy, Please ensure that you have provide the proper value for initial velocity. Can you share the model file?
  10. Hi, Please go this tutorial http://www.altairuniversity.com/wp-content/uploads/2014/01/CFDacusolveflow1.pdf which is Pipe flow analysis using HyperMesh and AcuSolve. Also go through video tutorial available at https://www.youtube.com/watch?v=3MmzjVsH5P4 This may be helpful for you.
  11. Hi Oliver, You need to define the loading stress-strain curve for this material law. Please go through the Help Menu for /MAT/LAW70 where an example material card is shown. The material law 70 is used yo model visco-elastic foam like seat foam which do not have plastic deformation. To model crushable foam (with permanent deformation), user should use Material Law 33 or honeycomb material (law 28 or law 68). Please go through the tutorial available at http://www.altairuniversity.com/learning-library/modeling-and-analysis-of-honeycomb-impact-attenuator/ which is the 'Modeling and Analysis of Honeycomb Impact Attenuator'.
  12. Hi Subhu, Please go through this document http://www.altairuniversity.com/wp-content/uploads/2013/12/1036.pdf which explains about HyperWorks solver run manager.
  13. Hi Tiago, From the engine out file find what is causing for the time step drop. It can be an element, a node or an interface. •For an element, check the related material (especially its Young modulus and density in case of an elastic-plastic material; and its viscosity in case of a visco-elastic material). There must not be an error in the units system that this data is given in. Check the size of the element, since elemental length is proportional to time step. •For a node, check the characteristics of connected elements. If the node is on the master side or the slave side of an interface, this interface must be verified. •For an interface, the gap of the interface must be verified if some failure happens on the master or the slave side of the interface. Once this is cleared you can run the simulation without time step being dropped.
  14. Hi Monu, Please run the model with the engine file attached and then we will review the results. impact_final_0001.rad
  15. Hi Monu, Try with the attached file. If it's not working, please import the model_0000.rad file attached in the above post. model.hm