This New 7.0 Engineering version means New and Easier to understand fields, in plate options, when running TPI 2002 plating. It also means, a new tool, to help you visualize what’s happening to your design on the fly.
TPI, in conjunction with WTCA, has eliminated the minimum required Cq value for the Plate Placement Method (PPM). In fact, they have eliminated the separation between the PPM and the Tooth Count Method (TCM) totally. There is only one method now, although it does allow for you to count teeth instead of using the visual plate placement drawings if you like. The new method allows you to set the Fabrication Tolerance to whatever level that allows you to consistently pass inspections. If 100% of the joints that you inspect pass, then you might find that you can reduce the Fabrication Tolerance that you are using.
So, you may be saying to yourself- What do I do now? There are different default settings to remember in this version when I was just getting use to what was in the previous versions. Well, not really. There is just a more intuitive way of applying them. So, just sit back and relax as I explain.
I know that certain values and fields in the Engineering Software can be confusing- especially when it comes to plate settings. Not only that, they could mean the difference in being competitive in a design and having a chance at that bid. In some cases, we have added new features to help with your design performance that you may not be aware of when you get your new software. This article should help you understand the value added features we added for plating when using TPI 2002 requirements.
In creating the first job in 7.0 Engineering, you may notice that some of the plate options have changed. For instance, looking at the plate options now, I see a couple of new fields like: “TPI/QC Fabrication Tol. (%)”, and” Incremental Decrease of Fabrication Tol. (%)”.
“TPI2002 Percentage Defect Area (%) or CQ Factor” and “Incremental Decrease of Defect Area (%)” have been replaced, by these new fields, to make the feature more easily understood and to give the user more control over how much grip reduction (% defect Area) they want to use in their Quality Control Plan.
Let’s discuss TPI/QC Fabrication Tol. (%) first.
In Preparation for the new TPI 2007 requirements, TPI has allowed for the change from Cq factor to using this Fabrication Tolerance as the measure for how much of a reduction a user can take on the grip value of a plate to allot for defects. Prior to version 7.0, the Truss Manufacturer selected their Cq value, which in most cases was set to either 1.0 or 1.25 (taking into account 20% or 0% defects, respectively).
In version 7.0, the TPI/QC Fabrication Tol. (%) is now used to just put in the desired % defect area. So, instead of inputting a Cq factor of 1.00, you will now enter “20” for the “TPI/QC Fabrication Tol. (%)” in the plate options dialog box. Once again, the input value represents how much grip reduction (% defect Area) the user want’s to use in their Quality Control Plan.
In addition, you have control over a range of values which are:
The “TPI2002 Quality control factor (Cq)” under plate options has become the “TPI/QC Fabrication Tol.(%)”.
The “Flat Plate TPI2002 Quality control factor (Cq)” has become the “Flat _Plate_TPI_QC Fabrication Tol.(%)”.
Let’s now discuss Incremental Decrease of Fabrication Tol. (%).
The best way to explain this setting is to give an example and at this time I would suggest leaving the setting at its default unless you really understand its function.
Let’s say you have the TPI/QC Fabrication Tol.(%) set to 20%. You have set Incremental Decrease of Fabrication Tol. (%) to 4%. What will happen is that the program will run the plating routine at 20% reduction and if a failure occurs then it will reduce the Fab Tol. in increments of 4% until the plate works (as close to 20% without failure). This gives you the opportunity to have a plate with the most available defects without having a joint that will not plate.
Note: The setting “Use Existing Materials” prevents the changes in these values from being applied. Any changes to these values will only be applied when you redesign the truss- using Analyze Redesign.
New Tool in 7.0 to view Critical Joints.
Under Setup\Output Setup\Display: There is a new Switch you can turn on to Circle Critical Joints.
This switch allows the designer to view Critical Joints on the screen after Analyze or Analyze Redesign has been selected and the plates are displayed on the design. The Critical Joints (Any Joint with a JSI above .80 typically) are viewed as a Blue Circle around the Joint- indicating that it is a critical joint close to failure. It can be viewed as such:
This Tool can be useful to a person designing trusses because it provides a quick visual example and lets the user know which joints are critical; along-with, the number of critical joints there are. If the user wishes to reduce the number of critical joints on the fly, they can go to either plate options or plate editor and make the necessary adjustments, or they can make an adjust to the design web pattern and Analyze Redesign the truss to see the results immediately. No matter the outcome, the user will always be able to visually see the number of critical joints visually on screen.
I hope you find this document very useful. If you have any questions about TPI 2002 plating requirements, please contact your MiTek Engineer for further assistance. For all software related questions, please contact Technical Support or use the Help File to assist you in your answer.