Wheat stem moduli in vivo via reference basis model updating

A novel structural analysis method was developed and used to infer the in vivo material properties of an important crop species. In particular, reference basis model updating was used to reconcile the predictions of an idealized analytical model with the observed forced vibration response of living wheat, and thereby determine the effective longitudinal moduli of the tissues comprising the vibrating structure. The ensuing study of two varieties of wheat found that the stem tissue moduli decreased nonlinearly with height. These findings were in good qualitative agreement with the limited data available in the literature, and the updating procedure was highly effective in this unusual nondestructive testing application. To our knowledge, this is the first time that the reference basis method has been used to infer the spatially varying material properties of a living plant. Moreover, similar approaches could be used to characterize spatial variations in the material properties of other lightweight composite structures of arbitrary geometry.