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Tru-Flex LLC

West Lebanon, Indiana

Founded in 1962, Tru-Flex began in the garage of a West Lebanon resident, manufacturing small diameter metal hose for gas cans. Over the next 40 years, Tru-Flex saw strong growth driven by the need for metal hose in a variety industrial applications, and drastically expanded its product line. In the mid 2000’s, Tru-Flex began producing hydro-formed metal bellows for use in diesel exhaust systems. With the introduction of stricter emission regulations, the need for a leak-free exhaust solution had never been higher, and bellows sales quickly dominated. Today, Tru-Flex is the #1 supplier of hydro-formed bellows in the North American heavy duty diesel market, and is currently expanding its European operations with a brand new manufacturing plant in Poland. Tru-Flex prides itself on delivering high quality exhaust solutions and responsive engineering support to its many customers.


Our customers request a wide range of technical data on our products, such as durability and fatigue characteristics, corrosion resistance, stiffness curves, and thermal properties to name a few. In the past, we performed mostly experimental testing to satisfy customer requests, but are now moving towards simulation to serve our customers’ needs more efficiently and to use as a tool in the design process. With the complicated contact conditions of interlock and our own limited experience with FEA analysis, we requested IN-MaC’s assistance to help us create and validate our FEA models.  


Purdue worked with us through each step of the FEA modeling process, from model development through experimental verification. Additionally, they lent their expertise in contact elements and helped us realize time saving simplifications to our FEA models. They also recommended various technical resources, and even helped us to validate some of the test methods for RLDA (road load data acquisition) that we offer.


Purdue helped us reduce the time needed to run a bellows FEA simulation significantly through selective refinement of the FEA mesh, making parametric design studies more efficient and allowing us to return results to our customers more quickly. A typical simulation would take almost half a day to complete; we are now able to retrieve results in just a few minutes without a loss of accuracy.

These models will also allow us to perform multi-axial fatigue analysis using RLDA data, enabling us to predict the life and durability of our products in a particular application. With this information, we can implement design changes before production even begins, and help us to balance the cost and quality of our products to better serve our customers. 

Additionally, in many cases these models can be used to provide engineering characteristics of products to our customers, reducing or even eliminating the need for time intensive and expensive experimental testing and allowing us to turn around results much more quickly. For example, whereas stiffness testing may have taken a day or more to collect samples and perform testing, we can now simulate a stiffness test in a matter of minutes. 

We are beyond pleased with the outcome of our IN-MaC experience. Purdue has drastically expanded the capabilities of our engineering department, and we are now able to provide some of the most sophisticated engineering services of any bellows manufacturer. The technical expertise and quality of the Purdue faculty is among the best in the nation, and I would recommend their services to any Indiana business in need of technical assistance.”

- Nate Schaefer, Application Engineer

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