Polymers exhibit significant temperature-dependent mechanical response. Veryst tested a PEEK material at multiple temperatures and calibrated the PolyUMod® Three Network (TN) material model for finite element simulation.
Understanding composite materials’ impact response as a function of fiber direction is important for a wide range of uses, from automotive applications for crashworthiness to consumer product uses for drop and impact resistance. Veryst evaluated the high strain rate response of both glass fiber and carbon fiber reinforced PEEK (polyether ether ketone) using the Split Hopkinson Pressure Bar test method.
Veryst developed a new test method for measuring fracture toughness under impact loading that does not require measurement of load or crack length. We have used this method to help clients in the automotive and electronics industry understand how adhesives fail under impact conditions.
To compare the performance of two gas humidification devices, Veryst Engineering performed gas flow testing, device examination and CFD analysis.
An osteotome unexpectedly failed during a plastic surgery operation. Veryst was hired to explain the failure.
PEEK materials are increasingly used in a variety of industries with elevated temperature applications. This example shows how Veryst Engineering developed a temperature-dependent, nonlinear model of PEEK behavior for use in commercial FEA codes.
The peel test is widely used to measure the adhesion of thin, compliant films to rigid substrates. An accurate model of the peeling mechanics is required to extract the interface adhesion energy. Veryst used the PolyUMod® material model library along with a cohesive zone model of interface adhesion to simulate the peeling of a soft viscoplastic film from a rigid substrate.
A plastic clip used to retain a patient support failed, resulting in an occupant death. Veryst was asked to determine the cause of failure.
Polymer foams may exhibit extreme strain rate-dependence due to their structure. The low stiffness means testing the materials at high strain rates is particularly difficult. Veryst has developed multiple test methods to test and model these materials with our PolyUMod® library.
Obtaining accurate results from finite element analyses of polymers is not easy. Polymers are often highly temperature- and rate-dependent, exhibiting significant stress-relaxation, creep, and recovery. In this forming case study, Veryst examines the steps required to produce an accurate constitutive model of an example polymer, polyether ether ketone (PEEK), and shows the consequences of oversimplification.
All commercial FE packages provide material models for polymers, but Veryst Engineering’s PolyUMod® material library has advanced material models at the leading edge of polymer mechanics. We demonstrate the accuracy of a PolyUMod material model with native material models from Abaqus, ANSYS, and LS-DYNA.
Materials that have been deformed past their yield point and into the plastic strain region often display permanent deformation upon removal of load. How much of this deformation is truly permanent? Veryst has developed a method to measure the residual strain of materials following unloading as a function of time.
How long will a product last? This is an essential question during product development, but accurately predicting product end of life can be hampered by limited data. Veryst provides a method for the reliability engineer to predict end of life with a small sample size and shows how the proper lifetime prediction method can eliminate unexpected field failures.
Veryst can predict the ultimate strength and failure modes of design concepts generated using topology optimization and produced using additive manufacturing. We use advanced finite element analysis (FEA) that accounts for the nonlinear behavior of the material being used to make the part.
Tempered and plate glass are manufactured to produce very different fracture patterns when they break. Veryst can use this information to identify installed glass products and discuss the implications of their use.