Design of Piston Head-Crown (Stress Analysis)
Examing the art and science of piston crown with strain sensors.
The first question we should ask ourselves is, would you want to drive in an automobile that had no design requirements verified by physical measurement (only computer-generated data that used to qualify the automobile)?
As we all know, the piston crown configuration can change the performance of any engine, therefore, In this iNotes Video , Mike talks about the jewel ( foil strain gauge) in the crown (piston head). Mike shows how to measure the deformation of a piston head using Micro-Measurements strain gage sensors.
Usually the deformation is caused due to the periodic load effect.
The engine can be considered the core of any car or machine and the piston may be considered the most important element of the engine.
The piston is one of the key components in an internal combustion engine and the piston head receives the majority of the initial pressure caused by the combustion process. The Pistons are designed and manufactured with distinct features in the operation of an engine, these features closely relate to the machine performance, carbon emissions and driving efficiency.
Today’s structure and working environment of pistons are very challenging.
Many times, the mechanical deformation will cause cracks in the piston, therefore, it is essential to analyze the stress concentration of piston in order to improve its working reliability during operation.
Stress Analysis method with Micro-Measurements strain gages provides a great strain-stress calculation tool, thereof ensuring that the test and theory analysis method is better has become an important means for internal combustion engine performance study.
Why should I use strain gage sensors when I have an FEA model of my piston?
Computer models are useful tools for predicting structural performance, but they only tell part of the story. Metal foil strain sensor testing is performed to correlate the actual response of the part to test inputs with the generated computer model. Many uncontrollable realities can affect the FEA model, including complex structural design (not easily modeled), insufficient FEA mesh density, unknown or unaccounted for residual stresses in the part (often caused by the manufacturing and/or assembly processes), errors in material constants, unexpected interactions from other assemblies, and uncertainty in the applied loads (inaccurate boundary conditions). Perhaps one of the best questions to ask concerning strictly analytical design, (no experimental verification) is “would you want to drive in an automobile that had no design requirements verified by physical measurement (only computer-generated data was used to qualify the automobile)”?
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