Customer Applications of Vensim

Vensim can be used to solve a variety of problems. There are a number example applications at our corporate web site, in the literature, and of course in the models that come with Vensim.  Still, that is only a small sample of the things that can be done. 

Here are some of the areas in which our customers have applied Vensim.  If you have an interesting application you would like to share, please send us a note.

LNG Plant Design, Scott Johnson, BP

For analytic work in support of capital investment decisions the ultimate measure of success is not always clear. Plants and distribution systems that perform as expected in terms of throughput and uptime do validate the results of technical components of the simulation. Making such comparisons in detail is, however, costly and time consuming. In addition, changes in market and business conditions tend to have a very large impact on the economic value of infrastructure and the uncertainty around those is extremely high.

Many capital investment decisions are addressed using detailed discrete event simulations.  Continuously formulated Vensim models can be used to address the same issues and offer some improved transparency.  We developed a model to look at reliability and maintainability of a Liquid Natural Gas (LNG) plant using different assumptions on sizing and configuration.  While this model was not that much different conceptually from its discrete event counterparts, Vensim does have some advantages for presentation and analysis and we believe this is a worthwhile approach to developing models in support of investment decisions.  More information on this is available in a paper presented at the 2002 System Dynamics Conference.

Experimental Aerodynamics, Lucas Laroche, Laroche Consulting

In order to measure performance of aircraft wings it is necessary to have both a physical model of the wing and the experimental results showing wing performance.  Vensim's optimization and data handling capabilities were used to measure the lift to drag ratio as a function of velocity.  The control line airplane's movement is determined by the rotating velocity w and the inclination angle a.  Thrust (equals drag) is measured at the engine of the airplane using Hooke's law.  A Vensim model was used to estimate the underlying parameters, quickly and efficiently, in order to explore design alternatives.

For more on the results of this work see http://www.winggrid.ch.

Shock Analysis and Testing, Michael Talley

A new, efficient, easy to use 6 degree of freedom (6DOF) simulation method called Shock Isolation Mount Predictions & Loading Estimates (SIMPLE) has been developed and its use evaluated.  SIMPLE specifically addresses the need for practicality and efficiency by providing: 1) estimates of the excursion space needed for dynamic travel of mounted systems; 2) rapid prediction of responses such as acceleration, velocity, force, displacement, etc.; 3) a design tool for the location, sizing, and orientation of mounts for equipment and structures; 4) calibration via optimization; 5) multivariate sensitivity analyses of system parameters; 6) a shock mount library of more than 250 mounts; 7) inputs from floating shock platforms, deck simulators; medium weight shock test machines, etc.; and 8) immediate presentation of data after simulation.  SIMPLE uses systems dynamics programming to integrate causal relations into feedback loops so that system behaviors such as growth, decay, oscillations, etc. can be examined.  Shock isolated systems are characterized as 2^nd order feedback loops in the SIMPLE program.  A systems dynamics simulation environment called Vensim by Ventana Systems, Inc provides the workbench for programming the causal relations as well as the simulation and outputs necessary to examine behavior.

No special knowledge is required to use the new simulation method and no overcomplicated modeling assumptions are necessary to obtain reasonable estimates of isolated system responses.  For example, most 6DOF analysis tools such as finite element codes and specialized simulation tools require an extensive working knowledge and expertise to build and simulate models for shock isolated systems.  Calibrating and implementing multivariate and univarite sensitivity analyses with such tools would be even more complicated and time consuming.

More information on SIMPLE is available at http://webpages.charter.net/michael.talley

Tracking Team Skills, Peter Addor

In order to track the ability of a team to do its work it is necessary to know both how much skill the team has built up as a team and what the experience levels of the individual team members are.  By creating a matrix of team membership that includes both time with the team and individual experience levels it is possible to do this.  Using a fairly large array and the tricky SHIFT IF TRUE function it is possible to track team skills and their individual components with any desired degree of precision.

Positive Feedback, Bob Walker

Bob Walker discovered yet another use for Vensim  - naming his boat.  He created the graphic with the name and feedback loop and then had the sign company transfer that to the back of his new boat.  The result floats above the rest.