Finished FRP Project

FRP project has been finished. The report was submitted yesterday 10:00pm. The results can be summarized as

1. The stiffness can be predicted properly;
2. The ultimate load cannot be predicted due to the delaminating of FRP cannot be predicted;
3. To predict delaminating, stress concentration at the end of FRP must be modelled using much higher density of meshes near the end of FRP.

Future works on FRP:

1. FRP’s compression;
2. Effect of glue and connecting method;
3. Effect of stress concentration.

Report for 6th to 8th June 2005

CPG1 was analyzed in different mesh size.

• Finished running WCOMD to analyze CPG1-2.2, CPG1-3.3 and CPG1-4.4, and their results are similar. The initial stiffness if beam is MUCH higher than the experimental result.
  1. CPG1-2.2: 10cm x 10cm;
  2. CPG1-3.3: 20cm x 20cm;
  3. CPG1-4.4: 30cm x 30cm, stirrups are smeared
• Reasons: overestimate the thickness of FRP at soffit?
• investigate the blog features of blogsome, ModBlog, and livejournal at 8th June
  1. blogsome is suitable for research log which can backdating entry, set private for individual entry and clear; √
  2. ModBlog cannot backdating entry at present;
  3. livejournal’s user interface is not convenient.

痛心疾首，有限元模型丢失

当UCwinMesh 调用UCwinWCOMD是，提示WatchDog的驱动没有安装，于是我重新插入光盘安装WCOMD，在未清楚提示的情况下WCOMD卸载，我并没有在意这个卸载行为，认为WCOMD需要卸载后插上WatchDog再安装即可自动安装WatchDog的驱动。非常遗憾的是WCOMD在没有任何提示的情况下竟然同时自动卸载了我自己做的模型，造成无可挽回的损失，所有模型必须重新制作，而且并没有自动安装所需驱动，还必须手动安装。
教训

1. WCOMD必须用Export功能才能有效保存/保护自己的model;
2. WCOMD必须手动安装WatchDog的驱动。

Protected: Weekly Report from 30 May to 3 Jun

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WCOMD在划分单元时的限制

WCOMD是主要针对RC的FEA软件,所以在划分单元时有一些限制是适用于RC/PL的，但这些限制却制约了FRP的分析

1. 单元（包括overlapping单元）的最小宽度不能小于1cm，范围是[1,10000]，而对于FRP来说，FRP的厚度（宽度）往往<1cm；
2. overlapping plates只能是两层的；对于包含FRP、多层RC、PL的结构WCOMD无法model，只好简化为FRP+RC或FRP+PL两层；
3. 材料参数中，steel plate的密度（unit weight γ）不能小于50kN/m³,范围是[50,100];
4. 材料参数中，作为钢筋材料的steel plate的屈服强度不能大于1000MPa，范围在[100,1000]

Modelling of CPG1 in different ways to check the mesh size effect

The CPG1 beam was modelled based on Maekawa‘s zoning method。 However， some problems were found in the method。

1. When the reforcing bar is small and few, the RC zone would be small and even smaller than 200mm that is unfit for the control column of finite size;
2. 在厚度方向上用overlaping element时和针对稀疏的stirrups时，这个矛盾尤其突出；
3. 当只有单向reinforcing bar时，单元是作为RC处理的，但在没有reinforcing bar的方向上的tension stiffening/softening parameter c 如何确定？不应该还是0.4了，是不是该手算？
4. 把FRP 作为elastic material单独overlap上去应该是一个更加合理的简化方法，因为FRP并不像reinforcing bar一样对concrete产生类似的一些效应。所以干脆忽略这些效应而只假设FRP和RC beam之间是perfect contact的，还更合理一些。完成这个consulting project之后，在这个环节上可以看一些文献，做一些工作