A train derails with an ensuing fire and evacuation of a neighborhood. What was the root cause of the derailment?
Cohesive zone modeling is a powerful tool for predicting delamination in adhesively bonded structures. Veryst engineers use their expertise in experimental and computational fracture mechanics to calibrate cohesive zone models for accurate prediction of adhesive failure.
Composite materials, such as carbon fiber reinforced polymers, provide a high strength-to-weight ratio for structures ranging from aerospace components to biomedical implants to consumer sports products. These materials require thorough and specialized methods for material testing and validation due to their anisotropic material properties.
Medical devices, such as the cranial perforator here, show imperfections that are rejected by physicians. Veryst investigated the source of these imperfections and recommended steps to remove them.
Polymers are prone to deform slowly over long periods of time when subjected to applied load, a phenomenon known as creep. Over time, the deformation can grow so large that the part no longer functions as intended. Veryst utilized creep testing to compare material choices and set temperature specifications for polymers.
A high-strength reinforced hose failed in service under normal operating conditions well before its intended design life. Inspections of the subject hose revealed that failure was mainly due to delamination.
The nonlinear deformation and material relaxation associated with modeling the polymer screws for anterior cruciate ligament (ACL) reconstruction makes predicting key quantities such as stresses and holding forces challenging. Veryst, with its unique ability to test and model PLLA materials, was able to develop material and finite element models that predict the important short-term pull-out forces as well as the evolution of stresses over time.
Solvent bonding, although an effective way to join thermoplastics, can pose process challenges that reduce bond strength. Veryst uses FTIR microscopy to characterize the interface structure of solvent bonds, obtaining a “chemical image” of the solvent-bonded interface. The result is a full understanding of the bond and ways to improve its strength and reliability.
Guidewires and stents can become entangled during deployment. Veryst assisted in determining whether product design plays any role in these events.
Determining the mechanical behavior of bones can be challenging given the complexity of the materials that make up the bone and the geometry. Assessing the mechanical behavior of whole bones, especially rib bones, can aid in understanding the relationship between loading and injury risk as many rib injuries are due to impact type events.
Foam materials often exhibit high strain rate sensitivity, with large increases in stiffness as materials are loaded at higher rates. Veryst performed high-rate compression tests of a foam material, reaching impact strain rates of over 1500/s.
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.
Pop-up rubber jumpers are fun toys that unexpectedly jump and pop when placed on a flat surface after they are inverted. The poppers are hemispherical rubber domes which can be easily inverted inside-out, a process that stores elastic energy in the rubber material. This case study showcases how simulation can effectively be used to unravel complex nonlinear phenomena such as the inversion and jump of a popper toy.
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.