Formulating a Monte carlo simulation for corrosion initiation time

15 次查看（过去 30 天）
Barry Akenga
Barry Akenga 2017-4-16
评论： harsh Brar 2022-5-8
Hi, I am currently working on formulating a Monte Carlo simulation for predicting corrosion initiation time whereby the formula being applied is
T = X^2 / [4D(erfc^-1(Cth/Co)^2]
where X, D, Cth, Co are random variables with lognormal distributions for X,Co and Cth is a uniform distribution and D a distinct value.
Below is some of the code for the variables required:
X = normrnd(40,0.1,1,1000);
Co = lognrnd(3.5,0.5,1,1000);
D = 5*(10^-5);
Cth= unifrnd(0.6,1.2,1,1000);
E= erfc(Cth/Co);
Where the issue arises is when I try to implement the equation as the random variables are vectors so the power function becomes inapplicable as it requires scalar quantities. More information and assistance is kindly welcome.

请先登录，再回答此问题。

回答（6 个）

Image Analyst
Image Analyst 2017-4-16
I don't know about the erfc -1 versus the erfc, but how about this:
X = normrnd(40, 0.1, 1, 1000);
Co = lognrnd(3.5, 0.5, 1, 1000);
D = 5*(10^-5);
Cth = unifrnd(0.6, 1.2, 1, 1000);
E = erfc(Cth ./ Co);
T = X .^ 2 ./ [4 * D .* E .^ 2]
plot(T, 'b-');
grid on;
Simply use dot before any * / or ^ operations that use a vector.
  3 个评论
显示 1更早的评论
Barry Akenga
Barry Akenga 2017-4-17
The plot arrived at is a Lognormal distribution plot for the probability density function. Which is also the plot I want to arrive at for the pdf.
Barry Akenga
Barry Akenga 2017-4-17
Also I think I have made a mistake whereby, the random variables generation does not have a sigma(std) but has a COV(coefficient of variation). How are you able to generate the relative random variables for the code on matlab?

请先登录，再进行评论。

Pablo Benítez
Pablo Benítez 2018-5-30
Dear Barry,
I hope you are well. Interestingly, I am working on a similar research to yours, however, the time of corrosion initiation that I am looking for is for carbonation. Have you achieved to get the PDF for the initiation time?
I will be grateful to be in contact with you,
Regards,
Pablo
  2 个评论
Barry Akenga
Barry Akenga 2018-7-16
编辑：Barry Akenga 2018-7-16
Hi Pablo,
Apologies for the late response, I only managed to stumble across your query while perusing through outstanding mail on my inactive account. I did manage to conduct this research and obtain data through matlab. Is there anything in particular I may help you out on?
Regards, Barry
harsh Brar
harsh Brar 2022-5-8
hi barry,
Hope you are doing well.
Lately I have been working on predicting the service life of concrete on the basis of chloride induced corrosion using monte carlo. I have been trying my best to get results from the code but its not working. I was hoping if you could help me with your code. That will be of great help.
looking forward to hear from you soon.
thank you.

请先登录，再进行评论。

Pablo Benítez
Pablo Benítez 2018-7-19
Hi Barry,
I hope you are going well. Fortunately, I managed to solve the problem of obtaining the time of corrosion onset by carbonation. I have had some problems to perform the Monte Carlo simulation at the beginning, but the problem has been fixed. Anyway, thanks for your response.
Best regards,
Pablo
Barry Akenga
Barry Akenga 2018-7-19
Hi Pablo,
Thanks for getting back to me on this, are you able to convey the code you used to obtain the results required for your Monte Carlo simulation. I did this during my final year for my thesis, however I went a step further and refined my data obtained from the Monte Carlo simulation to obtain variable specific data. Thanks in advance.
Regards, Barry.
Pablo Benítez
Pablo Benítez 2018-7-20
Hi Barry,
I will need to talk to the colleague who helped me with the programming. The code for MCS comprises a part of a larger code that was made for the maintenance planning of structures. Thus, the complete code is currently being reorganized to make a commercial package that will be used for decision-making. So, I do not know if there is any confidentiality to convey a part of the code. If there is no problem, I will send you.
Cheers,
Pablo
Abdelrahman Abdallah
hi barry,
I am working on the same equation and I just wanted to know
did you use the erfinv in matlab and why didnt you use lognrnd(log(3.5),0.5) for surface cholride

类别

在 Help Center 和 File Exchange 中查找有关 Genomics and Next Generation Sequencing 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by