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Old 06-28-2005, 02:49 PM
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Default What is Modulus???

What is Modulus???

Modulus, for history buffs, was coined by Thomas Young (circa 1810), an English physician and physicist. He gave the word energy its scientific import, and Young's modulus, a constant in mathematical equation explaining elasticity was born. For design engineers, this meant that at low tensile stresses, there is a linear or proportional relationship between stress and strain (known as Hooke's Law) and the slope of the strait line is (you guessed it) modulus of elasticity. In the 21st century, the above equations are critical for advanced composites which utilize a combination of resins and fibers, customarily carbon/graphite, kevlar, or fiberglass with an epoxy resin.

The fibers provide the high stiffness, while the surrounding polymer resin matrix holds the structure together allowing infinite design capability. In general, carbon composites are two thirds the weight of aluminum, and two and a half times as stiff.

All this means that graphite composites as we know them have a high tolerance to bending. The higher the modulus, the higher its tolerance. Graphite is resistant to fatigue, and can handle harsh temperature fluctuations. Perfect for the walk-in fisherman--right? To you fishermen out there: a rod touting a higher modulus rating will be stiffer or bend less than a rod with a lower modulus rating. Be careful though. Remember that these composites have an infinite design capacity.

That means marketing has unlimited means with which to present modulus. Since there are no industry standards that I am aware of, there is no way to compare apples to apples, i.e. the modulus of say IM6 to one manufacturer will not be the same as the modulus of IM6 used by another manufacturer.

Of greatest importance in my opinion, is the design of the mandrel used to manufacture the blank and the quality assurance of the end product based on the composite being used. Rather than talk modulus, I like to talk performance with my customers. Under what conditions are you fishing? What are you fishing for? What are the characteristics of your ideal rod in this given situation. Now I know what the customer wants. Forget modulus, you don't need to be a physicist or a design engineer. I can help them select the rod based on performance required. We can discuss power relative to stiffness of the rod desired, the action which is relative to the taper design. I use G.Loomis blanks, not because of my knowledge of modulus. I use G.Loomis blanks because I like the overall rod performance . . .power, accuracy in casting, weight, and sensitivity . . . look at the tool required for the job. ~

Mike Mattox, D&E RODS
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Old 09-27-2008, 05:53 PM
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Default Re: What is Modulus???

Interesting piece on modulus.
I share your enthusiasm for Loomis blanks.

Graphite, a primer on rods!
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