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标题: Solidworks smulation 设计分析自行车车架 [打印本页]
作者: 寂静天花板    时间: 2015-9-24 19:05
标题: Solidworks smulation 设计分析自行车车架
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草图、焊件和静态算例，优化车架几何结构，再用CFD分析，从空气动力学角度优化管形状。
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上图吧。
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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.
+ C. d1 J# c0 |& g$ fIn 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.
- g  x, A3 r# v. Y, g! a  S) w( p' j
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Analysis (computational) times are much lower for shellsthan solid geometry.
  G: _) \8 h0 o$ a) d* mFurthermore, laminar edges (coincident surfaces) aretreated as bonded, so there is no need to worry about knitting your surfacesbefore starting your analysis.
! |+ H* G1 o( Z" J( s5 n# D[attach]365869[/attach]Tapered 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.
$ M  F- r$ `7 G& _The main forces applied to the bike are torsional andlateral forces. Therefore, we can limit our analysis to torsional and lateralstiffness.
" z# \0 n' Y' w/ h# w
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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.7 d) z  z' W: {1 b& x
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).
( n# p, O& m" ?- A
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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.
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Thank you for reading, stay tuned forthe next part!
Summary of results
    
Design Aspect
      
Change In Stiffness (%)
   ( K6 c$ z1 x! K; w  y: d1 u' l
    
Non-Circular Profile
      
37 (Torsional)
   3 d0 I# T8 r* E6 K3 P9 r
    
Tapered Head Tube
      
21.5 (Torsional)
   4 M4 d0 q" ^$ m$ P' x
    
Non-Symmetric Chain Stay
      
11 (Lateral)
   2 w& D  b( b* D8 N( V% B* }' S
    
Seat Stay (+/- 1 mm thickness)
      
<<1 (Torsional/Lateral)
   8 z2 [" N) }  r0 b$ v
    
Top Tube Taper (1 1/10)
      
3 (Torsional)& }! s+ z3 ?, z! ]2 R1 U

  j4 _$ G" C. H7 t* l4 t- Q
/ O' q9 P* ~8 _3 G% e8 G2 Q2 I2 w这篇文章给人印象深刻的不是分析，而是自行车架的3D草图。不要抱怨软件如何如何，还是多检讨自己吧。
  



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