×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

#### Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

# Plotting Fixed Moment Diagram in PTC Mathcad Prime 7

## Plotting Fixed Moment Diagram in PTC Mathcad Prime 7

(OP)
Hello engineers. I wrote a mathcad worksheet using ptc mathcad prime 7 for analysing a three-span continuous beams using three-moment equations. I have calculated the reactions, fixed and free span bending moments. I have also plotted the free span moment diagram. I have not as yet drawn the fixed bending moment diagram. I was wondering if someone could help me to express the fixed bending moment as a function of x, i.e M(x). This will enable me to use the principle of superposition to draw the final bending moment diagram.
The diagram below is basically what I want to plot in mathcad.
Thanks in advance for any suggestions that may help me in this regards.
Yours truly
Bello Ali

### RE: Plotting Fixed Moment Diagram in PTC Mathcad Prime 7

you can write this as a discontinuous function that is linear within the desired regions. you want for x<l1 the moment to go from M1 to M2 so M1 + x*(M2-M1)/L1 should give you the desired values. You continue that concept through the full length.

### RE: Plotting Fixed Moment Diagram in PTC Mathcad Prime 7

You can do this with an integral. The integral of the shear function is the moment function.
Just make sure the range of integration is continuous.
0 <= x <= 2 and 2 < x <= 4 is continuous from 0 through 4
0 <= x < 2 and 2 < x <= 4 is not.

### RE: Plotting Fixed Moment Diagram in PTC Mathcad Prime 7

I have gone through this in mathcad 15 and mathcad seems to struggle with integration over a discontinuous function.

I was able to solve this by integrating of the continuous portion of the function and then adding tip to tails to connect the discontinuous regions.

Shear diagram (discontinous function)

Integration over continuous portions:

Adding tips to tails to make a final graph:

You can probably do something similar for your example.

S&T - www.re-tug.com

### RE: Plotting Fixed Moment Diagram in PTC Mathcad Prime 7

(OP)
Thanks @structSU10 for your prompt reply. I have tried your suggestions and was able to plot the fixed bending moment diagram. Thank you once again sir/ma for your heip

#### Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

#### Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

#### Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!