Development of a high performance guard rail system using wood-composite materials

The Department of Organic and Wood-Based Materials of the Insitute for Building Materials, Solid Construction and Fire Protection (iBMB) cooperates with two industrial partners to carry out the project
"Development of a high performance guard rail system using wood-composite materials"
(Entwicklung von Hochleistungsschutzplanken aus Verbundwerkstoffen auf Basis nachhaltiger Rohstoffe).

The goal of the project is developing a secure, sustainable, and durable guard rail system for traffic routes using a combination of classical (wood) and modern (eg. fiberglass) materials. To do this, high performance composite materials will be combined with local reinforcement, energy absorbing core, and corrosion-resistant renewable materials. The new guard rails will be compatible with the existing steel guard rail system.

The Wooden Guardrail project has yet gone through many milestones. Initial scaled specimens were created to help validate a finite element material model used to determine the energy dissipation in a 100 Joule pendulum test. This was then used to design a 1000 Joule pendulum. The unique new pendulum, which is instrumented to measure strains, load, accelerations, and rotation angle at high speeds, is now being used to test much larger specimens. These specimens are also scaled down from the size desired in a road guardrail, but are large enough to take into consideration the influence of year rings, knots, and other variable parameters of wood. This is an exciting step for our institute, to use the instrumented pendulum for investigating the dynamic properties of wood in this specific energy and velocity range, which has not been done before for this application. Future collaborations with the local, and market leading digital image correlation firm GOM, will provide crucial information about verification and validation of wood dynamic properties. This project has also researched the effect of various adhesives, wood species, and glass fiber thicknesses for optimization of the mechanical and durability performance of the guardrail. We see many great possibilities ahead in this project, from making safe, sustainable, and aesthetically pleasing roadsides throughout Europe to in depth analysis of finite element models applicable for different wood species.

Wood - being a carbon sink, is sustainable because it reduces the total global warming gases in the atmosphere.

The project is supported by the "Zentrale Innovationsprogramm Mittelstand (ZIM)" of the BMWi

Project number (Förderkennzeichen): KF2178805WZ2

Big pendulum test

Small pendulum test

Pendulum test on a non-reinforced specimen. With these tests the impact behavior is replicated on a small scale. The video shows the test in slow motion.

FEM Simulation of the pendulum test

The goal of this simulation is to calibrate the parameters of the Finite Element Model to the results of the pendulum test.

The diagram shows the energy expenditure for breaking the non-reinforced specimen, as calculated by FEM. The result is approximately 10 Joules. The range of the pendulum test results is from 4.41 J to 15.30 J, with an arithmetic mean of 9.9 J.

Test Setup

The pictures show the setup of the pendulum tests and the high-speed camera, which was used to take the videos. Despite the strong illumination, the video is quite dark due to the high frame rate.