Super Power or Buckling?

I am sure this has happened to everyone, you are working with a tool and suddenly the tool bends. You wonder if you have suddenly gained super-powers as they show in the movies. I wish it were true, but most likely the component buckled. 

Buckling refers to sudden large displacements due to axial loads. Slender
structures subject to axial loads can fail due to buckling at load levels lower
than those required to cause material failure. Buckling can occur in different
modes under the effect of different load levels. In many cases, only the lowest
buckling load is of interest.

My friend recently experienced buckling on his plant water sprayer handle. He too claimed he had the power to move the world. I fired up SolidWorks Simulation to check if we got some insights into the design. 

 

 



First we ran a static test to check how the part faired. It is here we realized the load was not sufficient to cause yield. Then the thought came to check for buckling. SolidWorks Simulation calculates Buckling load factor or buckling factor of safety. The buckling factor of safety (BFS) is the factor of safety against buckling or
the ratio of the buckling loads to the applied loads. 

The set up for buckling and static test remain the same. After running a buckling study you can plot displacements. These displacements or mode shapes ilustrate the profile i.e displacement of nodes relative to one another. We can typically ignore these displacement values. What we are interested in is the critical load factor displayed on the upper left hand corner. 

A model can buckle in different shapes under different levels of loading. The shape model takes while buckling is the buckling mode shape. When buckling is critical design factor, calculating multiple buckling modes helps in locating the weak areas of the model. If Buckling load factor is between 0 and 1; The applied loads exceed the estimated critical loads. Buckling is expected. In this case Buckling load factor of 0.98 shows buckling would occur at the red spot.

New sprayer-handle design

The replacement bottle sprayer-head looked nothing similar to the old one. Well I guess someone figured this out and made design-changes accordingly. 

Super Powers not so nuch.... Simulation is the way to go.

Rajat Trehan

Product Manager : Simulation 

Computer Aided Technology Inc.

 

 

 

Power on : SolidWorks Flow for Electronic Components

To optimize the thermal performance of electronic components and ensure their operation, designers and engineers need to simulate both the environment and heat loads in and around components, PCBs, and complete products. SolidWorks Flow Simulation, augmented with the Electronic Cooling Module, enables you to easily perform complete thermal analysis and test design changes during the design phase.

Lets consider a halogen floodlight with an aluminum housing, which contains a quartz glass front window, a silicone gasket, an aluminum internal reflector, a ceramic lampholder and a 150 W linear halogen lamp.

The lamp operates with 110 V current and the goal of this test the temperature of the lamp. Components of the floodlight and the halogen lamp are shown below.

Flow Simulation has a simplified wizard to set operating conditions, room temperature of 20 C and atmospheric pressure of 14.7 psi. Using the electrical conditions tab we can set the input voltage to 110V. 

Once all the material properties have been specified the software calculates temperature patterns based on conduction, convection and radiation calculations. 

Looking at the results obtained, we can conclude the glass cover and lamp bulb operate at permissble temperature.

Rajat Trehan

Product Manager : Simulation 

Computer Aided Technology Inc.

SolidWorks Simulation Bonded Contact Condition

The bonded contact condition in SolidWorks Simulation can be
used to accurately handle load transfer in a multitude of cases where bodies
stay in contact such as welded or glued bodies among others.  The software achieves this through two
methods; aligning the meshes of the two bodies hence bonding the nodes of the
two bodies (compatible) or by applying equivalent internal equations to the
contact interface to achieve the same result (incompatible).  The latter is of course used in situations
when the mesh does not allow for compatible bonding.  You can control when to use which inside of
the property manager by selecting the options at the bottom. 

 

Incompatible bonding is achieved in two ways as well.  Simplified bonding applies the equation only
at the nodes which lie completely within an element on the opposite body while
mortar or more accurate bonding applies the equation at all the nodes down the
entire line of contact between the two bodies. 
Through the study properties, you can choose to use either option or
leave it up to the software by selection the automatic option.

 

In the case when a mid-surface is used to mesh the body with
shell elements, it is paramount that this is accounted for when using the
bonded condition.  While the two bodies
might be clearly touching, the mid-surface is NOT the contact surface and so
applying the bonded condition directly on it will over stiffen the study.  In this case, you must use the offset option
when defining the shell to account for the gap between the mid-surface and the
contact surface.

 

Simply select the surface used to create the shell and then
insert the distance between it and the contact surface and the software will
account for this mass when applying the bonded condition as the load is transferred
from one body to another.

 

Brian Adika
Applications Engineer, CATI

SolidWorks Simulation Free Trial - Try SolidWorks Simulation Free for 30 Days

Try before you buy with a complimentary 30-day evaluation of SolidWorks Simulation Professional!

Here's how it works:

To help demonstrate the value of Simulation Professional, Solidworks will be hosting introductory customer webinars focused on the Value and ROI of Simulation Professional. Sharing examples of how a company can recover their complete investment of Simulation Professional in one use.  All you need to do is attend one of the following webinars to receive your SolidWorks Simulation Free Trial.  

Be sure to list CATI as your SolidWorks Reseller when registering.

Wednesday, July 18, 2012
10:00 AM - 11:00 AM CDT
 REGISTER NOW

Tuesday, July 31, 2012
10:00 AM - 11:00 AM CDT
 REGISTER NOW

So what are the requirements to get your Evaluation?

• You must currently use SolidWorks version 2009 or higher.


• Register and attend just one of the webinars.


• After the webinar, you’ll receive an access code to take advantage of your 30 day trial of one of the most comprehensive design analysis tools available.

To enhance your experience even further, you will also be given access to a simulation support portal and live technical support via Q&A webcasts and E-mail throughout the trial.

Are you ready to step up by reducing material and physical testing costs? How about saving time while creating innovative new products?

Get the power of Simulation Professional for 30 days and optimize your design analysis experience.

 

Jim TeDesco
Marketing Computer Aided Technology, inc. 

Register for the SolidWorks Webcast Series - June

The Equinox - Shorten your day with SolidWorks DATE: FRIDAY, JUNE 15TH Please join our local technical experts for our monthly complimentary Webcasts as we introduce our family of solutions, and outline benefits of our products for your business needs. When registering, be sure to list Computer Aided Technology, Inc. (CATI) as your SolidWorks Reseller.   Friday, June 15th - 12 PM ET/11 AM CT Premium Ideas to Shorten your Work day Presented by: Jeff Osman Area Technical Manager Get the most out of a short workday with these easy to implement solutions in SolidWorks Premium.   Friday, June 15th - 1 PM ET/12 PM CT Breeze through Flow Simulation Presented by: Matt Derov Simulation Technical Manager See how SolidWorks Flow Simulation can easily model complicated flow behavior of Liquid and Gas. Solving complex engineering fluid dynamic problems has never been easier.   Friday, June 15th - 2 PM ET/1 PM CT Shape up your Process Presented by: Kurt Anliker Area Technical Manager SolidWorks Enterprise PDM can help you take control of your engineering design data and gain valuable insight into your company's processes.   Friday, June 15th - 3 PM ET/2 PM CT 3D Documentation Saves the Day Presented by: Elton Smith Territory Technical Manager See how 3DVIA Composer can help your customers enjoy the long summer days, by giving them better documentation to keep their products working properly.

Register for a SolidWorks Plastics Webcast

Join us on April 19th from 9:30am -10:30am(CT) for you first look at SolidWorks Plastics.  SolidWorks Plastics brings easy-to-use injection molding simulation directly to the designers of plastic parts and injection molds. It simulates how melted plastic flows during the injection molding process to predict manufacturing related defects on parts and molds. You can quickly evaluate manufacturability while you design, to eliminate costly mold rework, improve part quality, and accelerate time to market.

When:

Thursday April 19, 2012
9:30am-10:30am Central Time 

>>Register Here<<

Topics Covered:

• Predict fill time


• Optimize gate location


• Air traps


• Weld lines


• Short shot


• Temperature distribution


• Pressure distribution


• Balance runner systems


• Family mold layout

 

 

Jim TeDesco
Computer Aided Technology, Inc. 

Register For a SolidWorks Simulation Webcast

Join us March 12th from 2pm-3pm Central Time for our SolidWorks Simulation Webcast. In this web presentation you will learn how to leverage 3D cad data to simulate real life behavior.  We will discuss how neglecting non-linear effects can lead to serious design errors. After reviewing examples from everyday design practice, you will see how non-linear analysis can help you avoid over design and build better products.  We will also study factors that influence component response to a vibration load, thus enabling mechanical designers to see a cost effective alternative to traditional approach of building, testing, modifying and retesting their designs.

>>Registration Link

Topics covered:

• Difference between linear and non linear test


• Simulate Plastic, rubber , foam components


• Simulate forced vibration


• Contact analysis

>>Registration Link

I hope you can make it to this presentation.  There is no cost to attend.

 

Jim TeDesco
Marketing
Computer Aided Technology, Inc.

Simulation and Motion Optimization

SW Motion is a great tool to understand kinematics of a mechanism. The  2012 version of Motion has a great new feature. If you use actuators and sensors to control the movement of a mechanism, you can optimize the entire design virtually. Typically, to get the system correctly configured would take many trial and errors on an actual machine or many hours of hand calculations.

 

A user can simply input sensors as a variable and the optimization tool to study range of motion. In addition constraints can be given to ensure SolidWorks motion find an optimum design for you. Check out this video…let me know how this will help your design processes.

Rajat Trehan

Product Manager - Design Validation

Computer Aided Technology Inc.

Help your Pressure Vessel Designs meet ASME Section 8 requirments.

A Pressure Vessel study combines results of multiple loads and understand behavior of any cross section as per ASME standards. A typical load includes internal pressure, temperature rise and earthquake loads. So to start with a user will create different static studies to understand design behavior under each load type (pressure, temperature, etc).

 

Using SolidWorks Simulation users can easily study the effect of multiple loads on designs.

 

 

Once a Pressure Vessel Design is run, users can use stress linearization to separate bending and membrane stresses. Simply define a section clipping on the stress plot, then right click and pick linearize. Pick any two points on the section and click calculate. The software generates six graphs for 6 stress components. Compare the numbers generated with ASME section 8 requirement.

So there you go, no need to fret over a Professional Engineer coming down every few weeks to clear your designs. You can use SolidWorks to help you out and assure him or her your designs conform to ASME standards

Rajat Trehan

Product Manager - Design Validation

Computer Aided Technology Inc.

SolidWorks Simulation Solutions for Electronics Packaging Applications Webcast

In this installment of the SolidWorks Webcast Series you will see how designers and engineers can test and simulate the thermal performance of their electronics designs.

When:
Tuesday, July 26, 2011
12pm-1pm Central Time

>Register Here - Be sure to list CATI as your SolidWorks Reseller when registering

Topics will include:

• Transient thermal simulations


• Joule heating


• 2-resistor simplifications


• Natural and forced convection cooling


• 15-minute Q&A session

>Register Here

 

Jim TeDesco
Marketing
Computer Aided Technology, Inc.

Simulate Performance of Your Sheetmetal Assemblies in SolidWorks

The June installment of the SolidWorks webcast series highlights the sheetmetal applications inside SolidWorks 2011. 

This webinar will focus on how SolidWorks Simulation tools can complement your design process by being able to digitally simulate and understand the performance of your sheetmetal assemblies under real world conditions.

 >Register Here

Topics include:

• Understanding the strength & performance of sheetmetal designs


• Light weighting designs without compromising on the performance


• Frequency and Vibration analysis of sheetmetal Enclosures


• Fluid Flow analysis in and around sheet metal enclosures


• Understanding the environmental impact of your designs

Tuesday June 21st
1:00PM EST (12:00 CST)

>Register Here

 

Jim TeDesco
Marketing
Computer Aided Technology, Inc.

Try SolidWorks Simulation Free For 30 Days

Here's how it works:
To help demonstrate the value of Simulation Professional, Solidworks will be hosting introductory customer webinars focused on the Value and ROI of Simulation Professional. Sharing examples of how a company can recover their complete investment of Simulation Professional in one use.

Friday, May 13, 2011
10:00 AM - 11:15 AM CDT
Register now

Friday, May 27, 2011
10:00 AM - 11:15 AM CDT
Register now

So what are the requirements to get your Evaluation?

• You must currently use SolidWorks version 2009 or higher.


• Register and attend just one of the webinars.


• After the webinar, you’ll receive an access code to take advantage of your 30 day trial of one of the most comprehensive design analysis tools available.

To enhance your experience even further, you will also be given access to a simulation support portal and live technical support via Q&A webcasts and E-mail throughout the trial.

Register Today - There are only 2 chances to take advantage of this offer!

 

Jim TeDesco
Marketing
Computer Aided Technology, Inc.

Fatigue Analysis of a Landing Gear using SolidWorks Simulation

It is observed that repeated loading and unloading weakens objects over time even when the induced stresses are considerably less than the allowable stress limits. This phenomenon is known as fatigue. Each cycle of stress fluctuation weakens the object to some extent. After a number of cycles, the object becomes so weak that it fails. Fatigue is the prime cause of the failure of many objects, especially those made of metals. Examples of failure due to fatigue include, rotating machinery, bolts, airplane wings, consumer products, offshore platforms, ships, vehicle axles, bridges, and bones.

Linear and nonlinear structural studies do not predict failure due to fatigue. They calculate the response of a design subjected to a specified environment of loads and restraints. If the calculated stresses are within the allowable limits, they conclude the design is safe in this environment regardless of how many times the load is applied.

Failure due to fatigue occurs in three stages:

Stage 1: One or more cracks develop in the material. Cracks can develop anywhere in the material but usually occur on the boundary faces due to higher stress fluctuations. Cracks can occur due to many reasons. Imperfections in microscopic structure of materials and surface scratches caused by tooling or handling are some of them.

Stage 2: Some or all cracks grow as a result of continued loading.

Stage 3: The ability of design to withstand applied loads continue to deteriorate until failure occurs.

Since Fatigue cracks start (typically) on the surface of a material. Strengthening the surfaces of the model increases life of model under fatigue events.

Using SolidWorks Simulation user can study the effect of a single load. In this case we study landing gear mechanism.  Note the wheels are not modeled. A total bearing force of 6000 lbs is applied to the faces that connect the wheel to the axle.

 

S N Curve or Alternating stress versus number of cycles required to cause failure at a given stress ratio is required to define material failure due to fatigue. A SN curve is based on stress ration or mean stress. The software uses linear interpolation to extract data when you define multiple SN curves for a material. A typical SN curve is shown in figure below

 

SolidWorks Simulation enables users to define different types of fatigue events: constant amplitude and variable amplitude.

Constant Amplitude Events

All cycles of a constant amplitude event have the same alternating and mean stresses. A constant amplitude fatigue event is fully defined by an alternating stress, mean stress (or stress ratio), and the number of cycles. A fatigue event can refer to one or more static studies, or to a particular solution step from nonlinear or modal time history dynamic studies. The software calculates the worst alternating stress levels for each event.

Variable Amplitude Events

A variable amplitude fatigue event is a load history record that defines the fluctuation history of load. The time values do not play any role for fatigue studies with a single variable amplitude event. In this case, it is adequate to define the amplitude sequence.

Fatigue results

SolidWorks Simulation gages fatigue on two parameters

 
Damage factor indicate the specified event consumes x% of the life. The maximum damage show 0.016% The damage plot shows that the axle is likely to fail due to fatigue failure after 1/(max damage) = 1 / 1.6 x 10^-4 = 6,238 blocks (repeats) of the specified variable-amplitude loading event. This result is verified by the total life plot as shown in the next procedure.

Based on damage total life of the mechanism can be figured out

 
Rajat Trehan

Product Manager - Design Validation

Computer Aided Technology Inc.

Event Based Motion Simulation

Using SolidWorks Motion Analysis users can model motion of an assembly that incorporates event-based motion control. For example, in  a manufacturing procress that includes components moving along a conveyor belt, motors turn on or change according to compoonent position along the belt. However, since you do not know the exact time at which a component reaches a position before calculating the motion, you cannot determine the time to change the motor value. Without knowing the exavt times to turn on or change a motor, you cannot creat a time-based motion study. However, you can use an event based motion study to model the conveyor assembly motion.   Use event-based motion analysis to specify motion from some combination of sensors, times or previous events.

Event-based motion requires a set of tasks. The tasks can be sequential or can overlap in time. Each task is defined by a triggering event and its associated task action. Task actions control or define motion during the task.

See below a video of how to set up event based motion and how you can improve motion of the assembly.

 

Rajat Trehan

Product Manager - Design Validation

Computer Aided Technology Inc.

 

The World is Non Linear

"The World is Non Linear" is the topic of my presentation at this years Solidworks World User Conference " SolidWorks World 2011". The conference is held from Jan 23 - 26 in the Henry B Gonzalez Convention Center at San Antonio TX.

I will be exploring Non Linear Simulation techniques, the need, approch to solve non linear engineering issures. This is a hands-on session, so attendees will practice concepts learned. It is a great opportunity to bring your engineering concerns to light and have multiple people discuss the approach.

SolidWorks World is a great place to meet people with an engineering acumen. This is one tech fest you do not want to miss. I am very excited to be a part of this event, I hope to see you there.

Rajat Trehan

Product Manager - Design Validation

Computer Aided Technology Inc.