Beware of Occam’s Razor or KISS when using a Strain Gage Sensor.

The vast technical data on strain measurement can make our job complex and confusing. Indeed, force measurements many times are complex and confusing. But more often than not they are neither. Regardless of the complexity, a successful measurement can almost always be accomplished when we engage with the environment and use a common sense approach. By dividing the measurement into logical steps, remembering that everything starts with the first step, applying a sound technical understanding to the problem will simplify the use of any sensor such as a strain gage.

Good designers, whether stress analysts, architects, or civil, mechanical and electrical engineers around the world all utilize Occam’s razor or KISS principle in their daily job, career, or calling. The simplest, most functional designs are usually the best. Indeed, the famed Bauhaus School of Design was a living testament of the concept. Its last director, the great architect Ludwig Mies van der Rohe (1930-1933), based many of his most famous buildings on the solid foundation of his well-known “less-is-more” design philosophy.

Another way to look at Occam’s razor when using Advanced Sensors Technology strain gages is the KISS principle – keep it simple strain vs. stress.

This principle has been a key and a huge success in every step of learning to use a foil strain gage sensor, both in force and strain measurements.

A common problem among civil, mechanical, electrical engineers, stress analysts and people in academia today is that they tend sometimes to over complicate stress-strain problems. The Occam’s razor or the KISS principle assume that if a large group of stress analysts cannot understand how to install a strain gage, it will be almost impossible to use the transducer properly or receive an accurate strain measurement from any stress concentration. Therefore, the intention by introducing the Advanced Sensors Technology and StrainBlog is that the widest possible audience in the stress analysis and transducers community should be able to understand how it works immediately for their case.

Typically, when we need to make a plan to measure any kind of force, pressure, load, torque or just a strain, we are faced with a challenge and sometimes a bias, so what we need to do is break it down into smaller pieces of stress concentrations that we believe are critical and then we build a process from a strain gage to a data acquisition system (DAS or DAQ) and  try to find the solution in a code. I would guess 6 or 7 out of 10 stress analysts make the mistake that they don't break down the stress-strain problem into small enough pieces. This results in very complex measurements of even the most simple problems. Another side effect is spaghetti measurement, something where we throw into the air a few suggestions about how to use a strain gage in our force mechanism or strain measurements and we end up with only a few assumptions that really stick and are correct.

Occam’s razor, however, should be wielded with prudence in all endeavors. Used improperly, the razor can reduce an elegant Mies van der Rohe structure to yet another I.M. Pei glass box, a radiant Rembrandt painting to the bleak fields of color in a Mark Rothko canvas of abstract expressionism, and a magnificent Beethoven symphony to either the atonal cacophony of an Arlonad Schoenberg composition or, it its ultimate misuse, to the noteless John Cage (non) composition, 4’33”.

When using Advanced Sensors Technology, Educators and stress analysts should apply Occam’s razor to their work with great care. Indeed, engineering students must learn the essential facts of math, physics, biology, chemistry, and mechanics just as thoroughly as they mastered the multiplication tables during their childhood. Yet, our future engineers must go beyond learning by rote that force equals the products of mass and acceleration. They should also be joined with Sir Issac Newton in the understanding of not only why the apple falls from the tree but also how the calculus he created quantifies its fall. The efforts of educators to impart these kinds of knowledge are far from vain.

William of Occam may well have found the articles and videos on StrainBlog to be an exercise in vanity. It covers a signal sensor – a foil strain gage – which is sufficiently characterized for most practical engineering applications. A foil strain gage, however, is not what the famous philosopher Immanuel Kant would have called a Ding an sich (“thing-in-itself”); a great deal is known about how it ticks and what its limitations are.

How can we benefit from Occam’s razor using a strain gage?

  • You will be able to measure more areas, quicker.
  • You will be able to prepare a measurement plan to measure complex areas of any structure and material.
  • You will be able to achieve more accurate force feedback or strain measurement than you ever believed.

How to apply the Occam’s razor when using Advanced Sensors Technology strain gages?

  1. Break down your measurement plan into small steps that you think should take no longer than a few minutes (not hours) to stick the gage.
  2. Measure the strain, then stress it. Not the other way around.
  3. And for all other measurements scenarios, try to keep it as simple as possible

When planning the way you intend to use a strain gage, whether for stress analysis or as a force element in your transducer, you need to keep it’s installation process as simple as possible.

Today, the Occam’s razor  or the KISS principle are mainly popular in the civil and mechanical design world. These principles are considered to be the key for all engineers and stress analysts that choose to work quickly and efficiently. Most people still tend to use many digital tools to measure and explain important issues that are related to strain-stress. The chance is that this experience does not come across smoothly and is not understood well.

yhernik's picture

Yuval Hernik

StrainBlog Editor in Chief