Category "Tips & Tricks"

The Challenge

Often when listening to a CIMdata presentation, their consultant will offer a tongue in cheek remark: “the most widely used PLM tool is Excel”. So, is it true? It is worth examining the issue in more detail.

Before proceeding, a better definition of the title is in order. The more accurate formulation – “Does an Excel spreadsheet contain the master definition of the eBOM during product design in your organization?”

There are two crucial points in this question

  1. Master definition implies that the BOM of record for final design is maintained in a spreadsheet
  2. eBOM is distinct from the mBOM maintained in an ERP system. Organizations generally do not use Excel for this purpose.

The Reality

BOM

So how prevalent is the master Excel BOM? If you are reading this article, you can answer silently for yourself. Aside from that, let us look at two data points:

Tata Technologies has conducted a PLM benchmark assessment at approximately 150 different organizations over the last 4 years. Based on our results, approximately 75% of these organizations use Excel in one form or another to control the eBOM.

Try a Google search on “Bill of Materials” and access the results for “Images”. Count how many of the images show Excel. By my informal count, at least 60% of the images from that search are Excel sheets of one form or another.

So, the prevalence of using Excel for eBOM would seem to be very high. Is that good or bad? Let’s examine that question in following sections.

The Good

Excel is perhaps one of the great inventions of the IT revolution. It is conceptually a simple tool but can be used in sophisticated applications. For generating and specifying a simple eBOM, it has the following merits.

  1. It is flexible and can be formatted in various was to portray an eBOM structure. The inherent layout of rows and columns is convenient for defining a structure
  2. One can add many columns to define and specify the various attributes of Parts in the eBOM
  3. Because Excel can easily perform calculations, the spreadsheet can automatically give aggregate results like total cost, total or sub assembly weights, total selling price, margins etc.
  4. It is a readily available tool across all businesses because of the persuasive nature of MS Office and everybody knows how to use it. Probably most businesses see it as an economical and inexpensive tool; dependent on budgets this may or may not be true
  5. Although it takes a little bit of dedicated formatting, the eBOM can show indented levels and collapsed sub-assemblies
Excel BOM
Excel BOM

The Bad

Of course, Excel may have some strengths, it has some significant weaknesses when it comes to eBOM management:

  1. It is difficult to do a BOM compare in Excel. Such functionality is required when two versions of the BOM need to be compared to see the differences
  2. Change Management in any Product Development environment is always a big challenge. While it may be possible to do revision control on an Excel spreadsheet (e.g. in SharePoint), it is impossible to do change control on individual parts in the eBOM
  3. Excel has no safeguards against anyone inadvertently deleting line items or details out of the eBOM.
  4. Calculations and formulas in Excel must be constantly checked to see they cover the correct ranges as changes will compromise these. Many companies have fallen to the problem of Excel formula mistakes
  5. By their nature, Excel spreadsheets are difficult to control and can proliferate easily, resulting in multiple copies. Which one is then the master?
  6. Excel eBOMs are always entered manually into ERP systems; requiring considerable effort and allowing the possibility of errors

The Ugly

Even if the “Bad” above is manageable, there are some situations where it is impossible to even consider using Excel for eBOM. Here are some of those situations:

  1. Large complex eBOM with part counts in the 200 and above range. No human can reasonably manage this in an Excel worksheet.
  2. Situations were the product has multiple configurations or variants. Because the number of resolved eBOM’s grow exponentially with the number of variants, it becomes impossible very quickly to manage
  3. When multiple downstream users must access the eBOM. This compounds the proliferation problem
  4. When the eBOM changes rapidly – keeping everybody up to date becomes impossible
  5. An eBOM is the very core of Product Development. Why use a half-baked tool?
  6. Excel cannot connect to any digital representation of the Part (3D model, Drawing, Specs etc.). This is a major shortcoming!

The Change

So, are you comfortable driving an automobile knowing that 66% of the eBOM sub-assemblies are managed in Excel?

There is technology that overcomes all the Bad and the Ugly. It exists today and is proven. The change to these systems may be difficult and potentially expensive but given the critical nature of an eBOM to a Product Development organization, it must be embraced!

Watch for the next article.

Tata Technologies is an engineering services company dedicated to engineering a better world. Visit our website at www.tatatechnologies.com

There is so much more to this command than welding. Not only is there a full range of weld types, but you can also model beads of adhesives, glue, and mastic as well as fasteners like rivets for example. Basically there are three categories in Weld Assistant for joining parts, they are: discrete welds, line welds, and adhesives. Normally a rivet is a type of fastener, but they are included as a custom weld in Weld Assistant.

In this post, let’s take a look at how to model rivets. We will create a custom spot weld to mimic a rivet. We will start by configuring a custom weld spot under File + Utilities + Customer Defaults.

  • From the Customer Defaults window, select Weld Assistant + Point Locator and then select one of the Custom tabs.
  • Set the Solid Display to Cylinder and give the custom Point Locator a name… Rivet for example.
  • Set the other attributes accordingly, and then select OK to finish the configuration.

Now create a Rivet the same way you would create a Resistance Weld Spot.

  • From the Weld Assistance command select Weld Point Wizard.
  • From the Weld Point Wizard block:
    • Select your Method
    • Set the Type to the new custom Point Locator you just created (i.e. Rivet)
    • Select Next.
  • Select the Face Sets and then select Next
  • Select the points you want to create Rivets at and then select Next.
  • Select Finish to place the Rivets.

If the Rivets don’t show up at first, then select the Solid Weld Point Display option.

Key benefits to modeling welds in Cad include:

  • Provides a key piece of information necessary for a complete Digital Twin.
  • Mass properties inclusion (Weight and Volume).
  • Easy to visualize.
  • Easy to validate for correct location using Weld Advisor.
  • Easy to convey information via a Drawing or PMI
  • Available for inclusion into CAE analysis
  • Available for process planning
  • Available for robot programming
  • Significant time savings compared to manual application of welds
  • Having the ability to create and validate the Rivets in CAD ensures quality data is being sent to manufacturing thereby reducing the amount of rework.

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Product and Manufacturing Information (PMI) consists of non-geometric data, that is attached directly to a 3D CAD model to define geometric dimensioning and tolerancing (GD&T), engineering and manufacturing specifications, dimensions, and text.  PMI is part of Model Based Definition (MBD) and together these two elements are a part of a Digital Twin.

Applying PMI to a 3D model can reduce or eliminate the use of 2D drawings and can be used downstream to perform tolerance analytics and coordinate-measuring machine (CMM) inspection.

PMI is a command within NX that gives you the ability to create/attach dimensions and annotations to define the 3D model, and requires model views similar to the views on a drawing.  These dimensions and annotations are associative to the 3D geometry, and if it is decided that a 2D drawing is required, then the PMI can be inherited from the 3D model and automatically applied to the drawing views.

We think of MBD and PMI as new technologies and 2D drawings as “old school,” but there are valid uses for a 2D drawing.  Given the ability in NX to quickly create 2D drawings with associative dimensions inherited from the 3D PMI… this gives you the best of both worlds.

The image below demonstrates what PMI looks like in a 3D model view, and the next image down demonstrates the inherited PMI in a 2D drawing view:

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NX Realize Shape is a powerful and intuitive subdivision design tool that makes use of primitive shapes to create concept design models.  In the image below you can see a sphere has been chosen, but there are a number of other shapes to select from such as cylinder or block to name a few.

These primitive shapes can be placed over top of background data like sketches or even art work similar to what you see in the image above.  When a primitive shape is created, a cage is automatically created that surrounds the shape.  The shape can be morphed into designs by transforming that cage.  By selecting on, and dragging the cage elements (lines or points), you can mold the shape to fit the background image.

 

As seen in the image above, you can split a face into smaller faces (subdivide) in order to create more cage elements. This gives you greater control of the cage anytime more detail is required in a given area of your design.

By selecting cage elements (lines or points) and dragging them up or down, left or right, the concept designer is able to morph a simple shape into a complex form in a relatively shorter period of time versus having to work with .

Why do we promote the use of Realize shape?

Simple, this model represents the birth of the digital twin.  This digital twin is then used for detailed design, documentation, validation, simulation, and all the way to traditional or additive manufacturing… all within a single unified environment like NX… means you are going to use trusted data from concept to manufacturing… without requiring conversion or translation, and this is going to shorten your innovation lifecycle, getting you from concept to market faster!

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One of the more common issues that come accross our helpdesk is the failed Vault log in attempt.  We try not insult the intelligence of anyone calling in, so we forego the typical first response of “Did you type your user name and password correctly?” or “Is the server on?” (I wish other technology providers would do this to…)

The first thing I will do in this situation is to see if the list of Vaults is accessible.  This will tell me that we have valid connection to the server.  The list of Vaults can be accessed by the button with the ellipses as shown below.

login

Clicking this button should then show you the list of enabled Vaults on that server, as seen here.

vaults

If you get an error message here, then I will try a couple things.  There may be a proxy server in your environment, or some other kind of IP route settings.  We can try using the fully qualified domain name (FQDN) or the IP Address, as seen in the two images below.  The FQDN should be pretty easy to decipher.  The pattern is server name and the domain name (typically the part after the @ symbol in you work email address).  An example is server.domain.com; server is the server name (a.k.a. host name, third-level domain), followed by a period, domain is the name of the domain (a.k.a. second-level domain), and .com at the end, which could also be .org, or .net (a.k.a. top-level domain).

fqdn2

The IP address may not be as readily known.  You may try PING‘ing the server, which, if successful, responds with the IP address.  Some smart IT folks will disable the ICMP protocol (which PING is a part of), so you may just have to ask your network administrator for the IP.

ip

There may be one more thing to try, and that is to append a port number.  Adding a port number is valid on any of the three methods above; server only, FQDN, and IP address.  To specify a port number, just add a colon and the port number to the end.  If your Vault requires a port, you will have to contact your administrator to determine which port to use.

port

If, after all of this, there is still trouble logging into Vault, then it may be time to seek helpdesk support.

Do you currently have a problem with migrating data from one system to another? Do you wish that the current manual method could be automated? Do your qualified staff spend time on the mundane activity of transferring data from one system to another?

If you answer yes to any of these questions, then Tata Technologies may have a tool available to solve these probelms – i Migrate It.

Picture2

This tool is an on-demand solution for any mannner of migrations and translations. It is configured for a given situation and allows for a user specify on demand what data he needs migrated and in what format.

From a user perspective, a typical workflow would be as follows:

  1. User logs into the tool. Configuration of the tool would determine what that specifc user is allowed to do (examine only, examine and migrate etc.)
  2. The user searches for the data that needs migration. Based on the search result, user chooses the exact data set required and specifies what must be preserved during the migration (full geometrical feature definition, brep only, metadata only etc.)
  3. Once all this is completed, the user would submit the job for processing. At this point, i Migrate It would take over and run the necessary background tasks required to complete the request. Depending on the nature of the systems, the job could take some time to complete (e.g. overnight batch process). The user has access to a dahboard that shows the status of the pending jobs and historical jobs.
  4. If the job fails (for example the requested data has already been migrated), the user is alerted with an error message which can be used to determine a future course of action.

This tool has several advantages for migration and translation problems:

  1. Only data that is really required by the users is migrated. This can reduce the cost of a complete migration.
  2. By providing options, the most efficent process is applied as determined by those who really know.
  3. After a period of time, usage will drop and the tool can be eventually phased out.
  4. Data remains secure during the process.

Consider this option when next you are faced with a migration problem!

A quick recap of Fluid Mechanics solutions from Dassault Systemes. It’s not a one offering anymore. With recent acquisitions of world class technology such as XFlow, PowerFlow and Exa the offerings span across a wide range of application from Navier-Stokes formulation to Lattice-Boltzmann formulation. Let’s get started:

  • FLA and FMK unite together: FLA has been an analyst role and FMK the designer role till 2018x. Starting 2019 GA, FLA will merge into FMK. That means all the functionalities of FLA will now be available in FMK. As FMK is a designer role with its own assistant panel, using CFD feature would be a much easier starting 2019 GA.

Both on cloud and on-premise options remain available. However, the basic prerequisite will be SEI that can be upgraded to SPI in case of existing customers. The bonus is that FMK role comes with enough tokes to submit an 8 core job 😊. Additional on-premise or on-cloud tokens can be used if needed.

Enhancements in Physics of Flow

  • Radiation solver available: The combination of CFD and thermal is now enhanced by adding one prominent mode of heat transfer that is radiation. The surface to surface radiation module is available in 2019xGA and surface to ambient module will be available in 2019xFD01. Emissivity and ambient temperature are the key inputs.

  • General solver enhancements: Mesh size independent convergence rate, better shock capture for high Mach flows, buoyancy dominated natural convection flow.
  • Comfort and e-cooling: Number of cabin comfort parameters for whole human body have been added for T&M as well as A&D industry. These parameters are based on ASHRAE55 specifications.

Enhancements in Meshing

  • Intelligent feature capture: In case of complicated surfaces with lots of geometry, surface mesher initially created fine mesh over the surface where fine features need to be captured. In conventional approach, the same surface mesh creates extra fine volume mesh inside the fluid domain resulting in extremely large volume mesh. The new intelligent feature capture option allows mesher to obtain coarser volume mesh using fine surface mesh.

  • Partition hex mesher: This application can be of tremendous use in FSI applications on the 3D EXPERIENCE Platform. While Hybrid Hex mesher is still considered a piece of diamond for fluid meshing applications, user may have requirement of hex meshing for the structural counterpart. As a result, hex meshing using partition approach (just like in CAE) has been introduced in the platform as well.

Enhancements in Scenarios and post processing

  • Duplicating scenarios: This feature was requested multiple times by many customers. There is often a requirement for duplicating scenarios in situations where one or more of the scenario parameter should be changed such as mesh parameter or any fluid BC while the user wish to retain previous scenario for sake of comparisons. Earlier, user had to recreate scenario from scratch. Now a duplicate option exists along with option of activating/deactivating scenario.
  • FEM Rep option: When Scenario app is launched, the UI asks the user whether to create a new FEM Rep or use an existing one.
  • Uniformity index: Additional output on scale of 0 to 1 to quantify uniformity of flow across a given section.
  • User Field Expressions: User can now create customized field expressions using standard field expressions with mathematical operators. Our Abaqus CAE buddies know it is a very useful field output capability that is now available in 3DX for fluid applications.

Enhancements in performance and stability

  • Automatic solver configuration: Let CFD engineers perform simulations rather loosing time in juggling with numbers!

The solver has been made increasingly mesh agnostic when it comes to convergence. Earlier with change in mesh, user was expected to manually change solver under relaxation factors to avoid problems of slow convergence or no convergence. Starting 2019x, these factors are updated automatically by the solver with change in mesh. Available in all incompressible steady-state flow.

  • Bad cells treatment: Let’s not penalize the whole model due to presence of only few bad elements!

In case of bad mesh that cannot be fixed, solver parameters need to me modified for the whole mesh and that too manually to obtain a converged solution. Starting 2019x, solver automatically detects such bad cells and simplifies or alter solution parameters only in those cells to obtain a solution.

Enhancements in user documentation

  • Verification guide: Verification guide has been introduced that can be accessed either from the SWYM learning center or from the HELP option of rich client install.
  • Theory guide: Provided for every feature in 3D EXPERIENCE Help starting 2019x GA. In addition to how to set up, information on underlying formulation is available as well.
  • Assistant Panel is an added advantage by default that would provide additional text information as well.

 

 

 

One of the noticeable change that has been made in 2019 solver is its capability to handle large models. SIMULIA has noticed that in recent past customers have shown increased interest in dealing with very large models with 2M degrees of freedom or more. There are multiple reasons for this requirement. First is scalability. More and more customers are interested in large system level simulations compared to part or assembly level. Second is fidelity and accuracy. Mesh size is getting finer to capture behavior at micro level instead of macro level.

When it comes to solving very large models, iterative solver has many advantages compared to direct solver such as less memory consumption, scalability and speed. A new hybrid iterative solver scheme has been introduced that offers more flexibility for choosing number of MPI ranks and number of threads per rank for a given node. These parameters can be defined in the abaqus_v6 environment file. This is equivalent to DMP+SMP allowing efficient memory management.

The iterative solver is available in 3DExperience 2018x FD05 and 2019x FD01 release. It supports many more Abaqus features compared to conventional iterative solver such as gaskets, friction, plasticity, creep, periodic boundary conditions etc.

This blog is a part of series “what’s new in SIMULIA 2019”. Please follow our blog site regularly for next blog article on this topic.

Simulations in Aerospace and Defense companies have a well-defined workflow. They have two separate teams for composites products: one for design and other for simulation. Composites ply design is primarily done by design engineers. These are the folks that determine the composites material as well as ply thicknesses and stackings in different regions of the composites part. CATIA composites design and manufacturing workbench has all sorts of tools to help designers achieve their objectives. We have discussed these workbenches in past.

However, because of FAA and other regulations in place, design has to be validated with FEA simulation and for most of the non linear workflows, Abaqus is the right solver choice. Though CATIA does provide an environment for Abaqus pre-processing, the preferred method in Aerospace industry is to use Abaqus CAE user interface. This is because of two reasons. First reason is better meshing capabilities offered by Abaqus CAE and second is tight coupling of Abaqus CAE with underlying solver. The obvious questions that arises is “how to move the ply information from CATIA to Abaqus CAE.”

The answer is composites link in collaboration with composites modeler for Abaqus CAE. The composites link exports the ply data from CATIA in form of layup file. Based on workflow, three options are possible.

  • Export only the ply data: When mesh is already in Abaqus CAE environment.
  • Export ply data with CATIA mesh: When meshing has been done in CATIA Analysis environment.
  • Export ply with external mesh file: When Abaqus input file needs to be merged with ply data.There are further options to export data either with or without taking change in orientations due to wrinkling into account as done by composites fiber modeler. Once the mesh and layup comes in Abaqus CAE environment, it is possible to explode the shell data based on ply thickness and create solid elements from shells. Abaqus CAE automatically creates section properties and assignments based on modified ply orientations. It is further possible to visualize ply orientations on each ply as well as ply stack plots on element by element bases. Once the data transfer and visualization is complete, the entire advanced analysis set up such as bird strike, fracture or delamination can be defined in Abaqus for analysis.

Computational fluid dynamics role of 3DX is the one going through tremendous enhancements compared to other roles available on the platform. In this blog article, I am going to highlight a few key enhancements with respect to the scenario modeling and the underlying solver.

Multiple reference frames

Most of CFD users are familiar with concept of moving fluid boundaries. Traditionally these problems have been solved using coupled Eularian – Lagrangian (CEL) techniques. In simple words this technique can be defined as a combination of two fluid spaces: one near the boundary in which fluid moves with the mesh and other away from the boundary in which fluid moves through the mesh. A whole new concept has been introduced in 3DX CFD to solve such problems. It is moving reference frames that can either translate or rotate with respect to a global reference frame. Either entire fluid domain or a portion of it can be assigned to this frame of reference. The governing equations are solved in this reference frame. Interfaces are created between moving and stationary frames to maintain motion continuity.

 

Compressible flows

Compressible flows become a concern when speed of flow is high. While this may not be relevant for companies designing exhaust manifolds or valves, an analyst trying to study the exterior air flow drag on a fighter jet moving at one tenth the speed of sound would feel the need of compressible air flow. The new release can simulate transonic flows up-to Mach number of 1.2.

Modeling of porous media

Are you looking to model components such as catalytic converters or air filters? Well, these products have a permeable medium that allows restrictive flow of air through it. Modeling such flows require porous media functionality that is now supported in 3DX CFD.

These along with many other enhancements are now a part of 3D experience 2018x platform. If you wish to know more, please feel free to contact us.

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