Recent content by jblakes

  1. J

    Volume fraction of multiple phases

    Yeah I can do, I currently have a sample that's 20x40mm. The treatment is for homonegisation of the material so should be the same, over time I am expecting to see an increase in delta phases and gamma prime and a decrease in laves phase. I have tried XRD but for some reason only showed the...
  2. J

    Volume fraction of multiple phases

    Afternoon all, Hopefully somebody can help me, I'm doing my final year project and it's looking at the effect of heat treatment on in17, when I run an XRD scan I found that I all the phases sort of hid behind the matrix and so can't really make them out. So I've been looking at using the SEM...
  3. J

    Diffusion equation: time for an element to diffuse at set distance

    Good morning, I'm trying to workout the time for an element to diffuse at set distance in microns. I have the distance, the diffusion coefficient, just unsure which equation I actually use. X= sqrt DT or the other one x= sqrt 2DT. I can't seem to figure out when you use one and not the...
  4. J

    Laminate properties (0/90) and (0/+45/-45/90)

    No, we have just performed a tensile and 3point bend test on a (0/90/0/90/0/90/0/90) 8layers (0/45/-45/90/90/-45/45/0) 8layers, the question i need to answer is how the stacking sequence effects the properties. I've tried reading laminate theory but just don't seem to understand. Am i right in...
  5. J

    Laminate properties (0/90) and (0/+45/-45/90)

    Evening all, im hoping somebody can help or point me in the right direction. We have tested these two laminates, one tensile and other three point bend test. The (0/90) has a higher uts, elastic modules, and flexure strength. (0/+45/-45/90) has a higher flexural modulus. Both roughly same...
  6. J

    MHB Damped spring differental equation

    Hi again thanks for your update. x(t)= c1sin(5√5t)+c2sin(5√5t)+1/109cos(4t) x(t)= 0 c1= -1/109 x'(t)= (-4sin(4t)/109)- c1(5√5sin(5√5t))/(2√t)+c2(5√5tcos(5√5t))/(2√t)st just checking this is ok before i sub c1 and -0.5 into x'(t) to get c2. solution will then be x(t) with values of c1 and...
  7. J

    MHB Damped spring differental equation

    Ok can you see if this is correct. y"+0y'+25=0 so roots are r+/-sqrt25 r=0+5i r=0-5i into y(t)= Acos4t+Bsin4ty(t)=0 y'(t)=0 0+0+125A=1cos(4*0) A=1/125 x(t)=Acos4t+Bsin4t+(1/125) x'(t) = 4Acos(4t)−4Bsin(4t) sub initial value into it x(0)=0 X'(0)=-0.5 X(t)= A+(1/125) A= -(1/125) x'(t)=...
  8. J

    MHB Damped spring differental equation

    Thank you. I'm guessing the second part. M(d^2x/dt^2)=0.2cos(4t)-kx.I'm guessing you rearrange to get d^2x/dt^2+k/mx=0.2cos(4t)/m then do the same process?
  9. J

    MHB Damped spring differental equation

    If I had worked it out correctly I would have got the same. Is that the answer to the question? I think I'm going to have to do some more reading. Do you do the same process for every first order ode?
  10. J

    MHB Damped spring differental equation

    So I'm guessing I do the step I did become Subbing x(0)=0.8 x'(0)=0 So therefore 0.8=c1+c2+ 299/625 -c1+0.3216=c2 X'(0)=0= (-25/2)c1+(-10)c2 Sub them into I get. =1.2864e^(-25/2)t-0.9684e^-10t Thank you for helping I'm literally learning as you post.
  11. J

    MHB Damped spring differental equation

    =-3.2e^(-25/2)t+4e^-10t I hope. I subbed x(0)=0.8 and dx/dt=0
  12. J

    MHB Damped spring differental equation

    Looking at the undetermined coefficient table then xp(t)=A. I'm guessing that's not what you mean?
  13. J

    MHB Damped spring differental equation

    Well I can't complete the square so assume I use quadratic equations so I get -10 and -12.5. Is that correct? Where do I go from here?
  14. J

    MHB Damped spring differental equation

    Hi Mark. Thanks for you reply. I don't really now what to do. I'm guessing it goes it the form. y"+22.5y+125=0? Dont know what to do with the g+(kl) /m side of the equation Regards James.
  15. J

    MHB Damped spring differental equation

    Afternoon All I have a math question I don't actually have a clue what to do. Can some help me out. A mass M is suspended vertically by a damped spring of length L and stiffness k such that the distance x between the centre of the mass and the top of the springis given by M (d^2 x)/(dt^2...
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