It is usually the same as the uniaxial E, unless the material is anisotropic (composites, wood, directional plastics, usually in which case you would need an orthotropic material model and many more properties). For linear, isotropic, and elastic, the Poisson's Ratio can be calculated from the Young's (E) and Shear (G) Modulus:Īs Shaun alluded, you can't get Young's Modulus (E) from Tensile Strength, unless the material is extremely brittle.įor ABS, if you need to work from that datasheet, the line you want is the "Flexural Modulus". If we use the Proportionality Limit of 0.125%, then you'll see we get the correct value of 200 GPa (250 MPa / (0.125%/100)).Īs for the Poisson's Ratio (nu), it depends on the material model. Using your method, you'd calculate a Young's Modulus of 1.25 GPa (250 MPa / (20%/100)), but we know that the Young's Modulus is 200 GPa. For example, A-36 steel has a yield strength of 250 MPa, and an elongation at break of 20%. To use your method, you'll need the strain for the Proportionality Limit. This point is well within the plastic region. Offset Yield Strength: This is a somewhat arbitrary point.Elastic Limit: Point at which further strains are plastic.Proportionality Limit: Point with Hooke's Law is (technically) no longer valid.True Elastic Limit: Point at which dislocations start to occur.If your material is linear, isotropic, and elastic, then there are four key points on a stress-strain curve: Furthermore, the strain of 23% is at the fracture point, not the yield point. This method works, provided your material is linear and elastic. Please be sure to include what version of the PTC product you are using so another community member knowledgeable about your version may be able to assist. You may also use "Start a topic" button to ask a new question. If you would like to provide a reply and re-open this thread, please notify the moderator and reference the thread. This thread is inactive and closed by the PTC Community Management Team. I have attached some Spec sheet that I often have to deal with Or am I missing it and the values are there. What values do I use from the Material Data Sheet do I use to calucate the Poisson Ratio - not given any axial or transversial strain values. If I remember correct Possion Ratio may not be a required value in ProMechanica (Could some confirm this as true or false)įor most common materials the Poisson's ratio is in the range 0 - 0.5. There must be values given from the material data sheets that can be plugged into a formula and then caluclate the resulting Possion Ratio. Math: 42.5Mpa / (23%/100) = (Not knowing the forces but given a maximum strain I use the maximum strain as control factor)Ĭould someone help me this this method given that most material suppliers never provide this value. Strain at 50 percent yield = 23% (sometimes these values are stated Strain at 50% elongation / 50mm/1minute Young's Modulus = Stress / Strain ( Standard Text Book Answer)Įxample: I have a material data sheet, attached. I would appreciate if someone could validate my formula and use of numbers from Material Data Spec sheets.
CALCULATING FLEXTURE MODULUS HOW TO
The question from client: "How do you or someone tell me how to calculate Young's modulus and Poisson Ratio if not given in the Material Specs."
CALCULATING FLEXTURE MODULUS ISO
Also I keep copies for ISO 9000 reasons.Ī client has has me a question and I gave him an answer as below you will see my method of finding Young's Modulus and Poisson Ratio. So sometimes I have to show or record Young's Modulus, Tensile Modulus, Possion Ratio, Density, etc in my reports. I have to perform FEA (ProMechanica) strucural simulation for them to show validatity of the design. I am a one man business and I do design and engineering for small companies.Īs an engineer, I often have to work with these clients and often they will provide me with material data sheet for plastics that they want to use.
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