Engineered Properties of Wood, Wood Materials and Structures
FS-FPL-4714

Problem 4:
Fundamental Research

I. Background

The goal of this problem is to develop data and procedures for characterizing the fundamental physical and mechanical properties of wood as a basis for use in other problems and for use by researchers outside the research work unit (RWU). This RWU retains the traditional FPL role of providing a storehouse of considerable wood property information on both domestic and foreign species. The Problem anticipates important projected needs through collection of additional data and through analysis of existing data. Further, this problem serves as a base for the development of general analytical procedures that address current and future research needs. Studies in this area will be focused on two types of investigations during the next 5-year period:

1. Questions involving wood quality effects on properties, and;
2. Broadening of fundamental property data required as input for analytical modeling of material or structural performance. As needed, statistical procedures will be developed cooperatively with the statistics RWU.

II. Body

A. Cell Microstructure

Of critical importance is gaining a better understanding, at a very fundamental level, of the effect of cell microstructure on mechanical properties. Analytical modeling of the relationship between cell microstructure and mechanical properties has not been attempted in a fundamental way in 30 years, at a time when computing capabilities were very limited.�

It is expensive and time consuming to study the effect of management practices, genetic selection, and chemical decomposition on wood properties, and even more costly to collect data on the changes in microstructure that result.�It is necessary to collect additional data in these areas, but the development of analytical models relating properties to wood structure at the micro- and macroscopic level will help maximize the value of experimental studies through the use of computer simulation.

This research complements other FPL expertise in identifying cell microstructure and the chemical composition of wood.�This long-term, multi-disciplinary research will establish a solid basis with wide application to wood utilization problems.

B. Effects of Moisture Content and Temperature

Fundamental information is also needed on the effects of moisture content, temperature, and changes in wood chemistry on the properties of clear wood. The information is critical input to computer modeling of material performance, especially for structural composites. In this Problem the approach will be to make critical evaluations based on the extensive knowledge base existing in the RWU to gain the most information with the least effort.

C. Planned Attainments

1. Improve our understanding of the relationship between wood microstructure and physical/mechanical properties.

i. Develop analytical models to predict the effect of changes in wood microstructure and physical/mechanical properties.

ii. Evaluate the effect of juvenile wood on the properties of selected hardwood species.

iii. Investigate the relationship between forest management practices and wood properties for selected hardwood and softwood species (cooperatively with scientists and foresters in other research locations).

2. Improve our understanding of the effect of moisture content and temperature on wood properties by evaluating the effect of extreme moisture contents and temperatures on the properties of selected hardwood species of importance for composite lumber products.

3. Improve our understanding of the relationship between wood chemistry and physical/mechanical properties by investigating the effect of decay on the properties of hardwood and softwood species. Investigate the relationship between hydrolytic chemicals and elevated temperatures on wood properties.

III. Conclusion

These attainments will help extend the Nation's forest resources by providing fundamental information on the effect of inherent wood quality on physical and mechanical properties that can be used to develop more applied solutions to resource conservation.�Fundamental information on moisture and temperature effects on the properties of clear wood will speed efforts to model processing and end-use performance of composite products from hardwoods species for which little is currently known.