Principal stress Definition and 19 Threads

  1. K

    Find the principal stresses in a shaft with torque applied

    Homework Statement Homework Equations M = Fd σ/y = M/I T/J = τ/r σalternating (σa) = σmax - σmin / 2 σmean (σm) = σmax + σmin / 2 soderberg: σa/σ'e + σm/σy = 1/FoS The Attempt at a Solution I am still unsure whether my progress so far is correct but.. I have calculated J to be 38.35e-9 m4...
  2. R

    Combined loading problem and failure

    Homework Statement The problem asks to find out whether the rod yields at points in section A according to the tresca and von mises criteria P is 120N Homework Equations Shear stress= VQ/It Stress= Mx/I shear stress= Tp/J The Attempt at a Solution I picked 2 points at section A. The...
  3. jan2re

    Principal stresses 3D, solving for direction cosines n1,m1,n1

    Homework Statement -4.882L1+M1+2N1=0 L1-2.882M1=0 2L1-0.882N1=0 L1^2+M1^2+N1^2=1 How to solve for L1 ,M1 and N1 ? 0<L1,M1,N1<1Homework EquationsThe Attempt at a Solution
  4. F

    Angle of principal stress vs maximum shear stress

    Homework Statement I'm having problem with the angle of $$theta_s1$$ . My ans is +35 (as in my working) , but the ans provided is $$theta_s1$$ = -55[/B] Homework EquationsThe Attempt at a Solution As in the picture posted
  5. C

    Angle between principal stress and shear stress

    Homework Statement I know that an element that is subjected to max shear stress is 45 degree away from position of an element that is subjected to principal stress.I couldn't understand why the θ s= θ p -45 degree? Cant it be θ s= θ p +45 degree ? Homework EquationsThe Attempt at a Solution...
  6. V

    How do I interpret multiple principal stresses for 3D loading with shear?

    For 3 D loading with shear, if I use the principal stress formula, say for x-y direction, two principal stresses are obtained. If the same is applied to y-z, two more principal are obtained, with one supposed to be common, but not. Thus I obtain six principal values, which cannot be used with...
  7. I

    (Composite) In plane principal stress or normal stress?

    Hey everybody, I went through a discussion with a colleague today about Finite element modeling of composite structures and how to interpret the stress analysis. I understand that for isotropic materials, principal stresses could be used against the allowable stresses to see if failure will...
  8. J

    Principal Stress: Get Help with Mechanical Systems Module

    HI everybody I am in dire need of help. I have started a mechanical systems module as part of a distance learning foundation degree. The notes seem quite sparse to me and I can't seem to get to grips with it from the start. I have attached a photo of the tutorial questions but the are no...
  9. Saumya Kar

    Von Mises stress Vs Principle stress

    Hello Folks, May be I am bring up the old topic again., but I've lost enough sleep over this topic. I understand that we use Von-Mises criteria for ductile material failure by comparing to yield limit and max principal stress is used to check failure for brittle materials. My question is bit...
  10. L

    On the physical meaning of principal stress

    Hi everyone, I was looking up Mohr's circle on planar stress and stress/strain relation and all that and I read a context on principal stress. It said that if there is both normal (tensile) stress and shear stress in a given area, then the principal stress at that location is greater than...
  11. S

    Principal Stress and Maximum Shear Stress

    Homework Statement Hi all, For my CW I have a question on a simple beam, ABCD and its cross-section. Please see attachment for figures The material of the beam is steel, where modulus of elasticity, E = 210 GN/m^2 I have been asked to calculate the principle stresses and the maximum shear...
  12. N

    Ansys Workbench- Max Principal Stress Error

    Hi all, I did simple problem, in which assembly is subjected to single load & it is fixed at other end. I used Higher Order Tet element (& tried with Hexdominent Method also) for the casting body. The vonmises stress shows the true results but when i was looking for the Max Principal...
  13. M

    Principal stress at surface of thin walled pipe

    Homework Statement See attached jpg for problem statement and diagram. I know we didn't discuss this type of problem in class. The rest of this homework set has been solving stress transformations with Mohr's circles for a given state of stress. I know how to find τxy (that was supposed to...
  14. T

    What are the shear and principal stresses for given stress components?

    id like to think i did this right, but i just want to make sure. i can't do symbols so let d equal sigma. the stress components are d_xx= 200 MPa, d_xy= 50 MPa, d_yy=-100 MPa. I need to find the max shear stress, and the principal stresses, and then a_s and a_p. heres what i got: max...
  15. B

    What condition defines a principal stress?

    What condition defines a principal stress? thx
  16. H

    Identifying Tensile and Compressive Stress in Principal Stress Extraction

    When extracting a Principal stress for the component, how to differentiate/seperate/identify the tensile and compressive stress in it?
  17. H

    Principal Stress, VonMises Stress , Fatigue

    1. I didnt understand why some people extracting Principal stress for aluminum material which is subjected to dynamic loads(acceleration).Why not Von Mises? 2. Which has more advantages in predicting Fatigue Life and how? 3. How will you distinguish between tensile and compressive...
  18. T

    Principal Stress and Strain on a Fracture

    Homework Statement Find the expressions for principal stresses in both plane strain and plane stress conditions sigma(x) = (K/(sqrt(2*pi*r)))*cos(theta/2)*(1-sin(theta/2)*sin(3*theta/2)) sigma(y) = (K/(sqrt(2*pi*r)))*cos(theta/2)*(1+sin(theta/2)*sin(3*theta/2)) T(xy) =...
  19. S

    What Is the Practical Application of Mohr's Circle and Principal Stresses?

    So I understand how to use Mohrs circle and the transformation equations to find principal stresses and stresses for a given plane, but what is the point? Is there a purpose to knowing this other than finding stresses for a given direction, the stress invariants or that shear does not occur on...
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