Will my PA66 (Nylon) beam plastic deform?

In summary, the conversation discusses a model that requires a 1mm vertical press and successfully displaces the desired amount with 30N of force. However, the Von mises stress exceeds the yield strength, causing concern about plastic deformation. It is suggested to evaluate the problem using classical analysis methods and to add fillet radii to reduce stress concentration.
  • #1
dsire4u
2
0
Hello,
I have this model that required to be pressed vertically 1mm.
I successfully displaced 1mm vertically with 30N of force.
Unluckily, Von mises stress goes way beyond the yield strength.
However, the strain is below the yield strain of 5%.
I do not understand how ductile/flexible material like Nylon will plastic deform with 30N of force applied.
Can someone explain to me if my model will plastic deform or not?
Please help,
Thank you
Included the x_b file of the part model.
model.PNG
Displacement.PNG
stress.PNG
Strain.PNG
 

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  • Nylon 66.zip
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  • #2
Have you done any evaluation of your problem using the classical analysis methods?
 
  • #3
JBA said:
Have you done any evaluation of your problem using the classical analysis methods?

I was not able to. I can only do evaluation of the straight beams...
 
  • #4
your primary concern is the bending moment tensile stress at the base of the angle cantilevered section. For a start , resolve your force vector and treat the problem as a cantilever beam connected to the base.

FEA is subject to a number of issues in its modelling, so it is important that you understand the basic principle elements of the force vectors and stress analysis that apply to the problem you are analyzing in order to evaluate the accuracy or its solutions.
 
  • #5
Two words.

Fillet radius.
 
  • Like
Likes Bandit127
  • #6
I am with Chris. Add fillet radii wherever possible but particularly around the high stress areas and re-analyse it. I would go for a radius of 25% of the wall section to start with.
 

1. Will high temperatures cause my PA66 (Nylon) beam plastic to deform?

Yes, PA66 (Nylon) plastic is known to have a relatively low melting point of 263°C, which means that exposure to high temperatures can cause it to deform or even melt. It is important to consider the operating temperature of your plastic beam to prevent deformation.

2. Is PA66 (Nylon) beam plastic prone to creep?

Yes, PA66 (Nylon) plastic is known to exhibit creep, which is the gradual deformation of a material under constant stress over time. This means that if your beam is under a constant load, it may deform over time. It is important to consider the loading conditions and potential creep when designing with PA66 (Nylon) plastic.

3. Can the shape of my PA66 (Nylon) beam affect its susceptibility to deformation?

Yes, the shape and geometry of your PA66 (Nylon) beam can greatly affect its susceptibility to deformation. Beams with larger cross-sectional areas or thicker walls will be more resistant to deformation compared to those with smaller cross-sections or thinner walls.

4. What factors can contribute to the deformation of PA66 (Nylon) beam plastic?

Aside from temperature and loading conditions, there are several factors that can contribute to the deformation of PA66 (Nylon) beam plastic. These include exposure to chemicals, UV radiation, and mechanical stress. It is important to consider all these factors when designing with PA66 (Nylon) plastic.

5. How can I prevent my PA66 (Nylon) beam plastic from deforming?

The best way to prevent deformation of your PA66 (Nylon) beam plastic is to carefully consider all the factors that can contribute to it, such as temperature, loading conditions, and exposure to chemicals and UV radiation. Additionally, choosing the right shape and geometry for your beam, as well as using high-quality materials and following proper manufacturing processes, can also help prevent deformation.

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