Solidworks smulation 設計分析自行車車架

寂靜天花板

Part 1: Frame Geometry Optimization –  Using 3D Sketches, Weldments, and StaticAnalysis to optimize the frame geometry

Part 2: Tube Shape Optimization 1 – UsingSurfacing and Static Analysis to define the shape of the tubes

Part 3: Tube Shape Optimization 2 – UsingCFD analysis to optimize the aerodynamic efficiency of the tube shapes

Part 4: Components and Details – Finishingup the rest of the bike. Because why not?

用3D草圖、焊件和靜態算例，優化車架幾何結構，再用CFD分析，從空氣動力學角度優化管形狀。

上圖吧。

When we want to incorporate FEA techniques in ouranalysis, we should consider ways to simplify our model. A bike frame has avery small thickness relative to its surface area. Therefore, we can analyzethe geometry using shells.
In SOLIDWORKS, shells are very easy to set up. With thehelp of the Shell Manager,surfaces can be given a thickness, material, offset type, and more within oneconvenient table.

Analysis (computational) times are much lower for shellsthan solid geometry.
Furthermore, laminar edges (coincident surfaces) aretreated as bonded, so there is no need to worry about knitting your surfacesbefore starting your analysis.
3 g  ?. v& Q& a  R0 u$ WTapered vs. Non-Tapered Head TubeThere is quite a lot of hype about ‘tapered head tubes’ inthe performance cycling world [where the bottom profile of the head tube tapersout], but how much of a difference does it actually make? To find out, I ran astatic analysis to see if there was any noticeable effect on the frame’sstiffness.
8 b: `: |2 {" }The main forces applied to the bike are torsional andlateral forces. Therefore, we can limit our analysis to torsional and lateralstiffness.
& a- g7 P) M$ k) I! P

These are simplified definitions for a body with onedegree of freedom. This can be applied to our case by analyzing the resultantdeflection in the direction of the applied force as long as one force isapplied at a time for each analysis.
First, let’s look at the torsional stiffness. In order tocalculate torsional stiffness (for the Head Tube) we can create a resultantplot of the circumferential deflection about the Head Tube Axis (HT AXIS).
; a! O6 m0 L% T, b5 p! L

By taking advantage of the extra spaceon the non-drive side, I was able to increase the lateral stiffness of theframe by 11%.

In the next part, I will furtherimprove the performance of the frame design by using CFD (computational fluiddynamics) analysis to optimize for aerodynamic performance.

Thank you for reading, stay tuned forthe next part!

Summary of results

    

Design Aspect

      

Change In Stiffness (%)

  
    

Non-Circular Profile

      

37 (Torsional)

  
  H: ^% R1 l1 v. ^     

Tapered Head Tube

      

21.5 (Torsional)

  
    

Non-Symmetric Chain Stay

      

11 (Lateral)

  
9 ]- B5 U, d6 ~( k) R1 m     

Seat Stay (+/- 1 mm thickness)

      

<<1 (Torsional/Lateral)

  
2 U/ L. ]4 L3 j; D     

Top Tube Taper (1 1/10)

      

3 (Torsional)
& h4 I( t& T# h6 T+ Y( s' v" n

2 g0 n" {2 M1 T5 I& \, T這篇文章給人印象深刻的不是分析，而是自行車架的3D草圖。不要抱怨軟件如何如何，還是多檢討自己吧。