George Laird's blog

CFD Analysis of CRRC's LACMTA Heavy-Rail Rapid Transient Vehicle

This has been an on-going project for our CFD consulting services team during most of 2018. As we all know, there is nothing like a “site visit” to meet your fellow engineers and see hardware. In early September, Drs. Laird and Hearn visited the CRRC Changchun Railway Vehicles Co., Ltd in Changchun, China. This is a cooperative project where Predictive has partnered with Hengstar Technology, Shanghai, China (Dr. Lu Hongsheng is shown on the left of our group photo). The project work requires a complete flow and thermal analysis of Los Angeles County Metropolitan Transportation Authority (LACMTA) new passenger transit vehicle. The CFD requirements are a notch above normal specifications with tight controls on air flow volume, maximum velocity and distribution. Thermal analysis looks at vehicle cool down on hot days (transient thermal with solar radiation and lots of internal heat generation) and also thermal management within the electronics and motor drive bay at bogie level.  All simulation work will be validated against vehicle mock-ups.

 

Changchun, China – CRRC’s Manufacturing Site

CFD Analysis of CRRC’s LACMTA Heavy-Rail Rapid Transient Vehicle 01

CRRC’s Bullet Train

STAR-CCM+ CFD HVAC Flow Analysis of Passenger Transit Vehicle

China News - LS-DYNA Implicit Class

LS-DYNA is historically known as the world's best explicit analysis code or the leader in the finite element analysis of nonlinear transient events. During the last ten years, LSTC (the manufacturer of LS-DYNA) has heavily invested in the development of its implicit anlaysis capabilities. Today, LS-DYNA can seamlessly handle complex, nonlinear analyses from static (implicit) to transient (explicit). Predictive Engineering has developed training course materials that covers both the implicit and explicit sides of the code. It was with pleasure that we taught a course in Shanghai, China to 27 students from industry and academia. This three day LS-DYNA training course was focused on LS-DYNA's implicit analysis capabilities from linear, elastic static stress analysis to static nonlinear analysis to fully, transient nonlinear analysis. The course finished with a half-day training on the linear dynamics capabilites of LS-DYNA.

 

Predictive Engineering LS-DYNA Implicit Class Photo - Shanghai China September 5-7 2018

 

15th LS-DYNA International Conference & Users Meeting

Every year, Predictive Engineering attends an LS-DYNA Conference, this year it was in Dearborn, MI and next year, it’ll be in Koblenz, Germany. The technical sessions covered a broad range of topics from "How To's" to new numerical algorithms to validation work between experimentalists and theoreticians. For me personally, these were the three stand-out talks:

(i) Modeling & Simulation Challenges at the Interface between Man and Machine: Medical Devices by Dr. M. Palmer
(ii) Modeling of a Cross-Ply Thermoplastic for Thermoforming of Composite Sheets in LS-DYNA by K. White and
(iii) An Enhance Assumed Strain (EAS) Solid Element for Nonlinear Implicit Analysis by T. Borrvall.

The first paper was by Medtronic and the background gossip is that they are moving away from other commercial solvers to focus on just LS-DYNA due to its multi-physics capabilities and especially its strong nonlinear implicit performance. The second paper was a stunner and showed how thermoplastics can easily reach their glass transition temperature under moderate strain rates. In essence, whenever composites are simulated under dynamic environments, one should consider temperature effects on the resin and how it will lower its elasticity. The third paper was just plain fun mechanics and how LS-DYNA is continually expanding its capabilities in the implicit arena.

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