A simple approach for assessing the quality of bender elements

Bender elements are frequently used in geotechnical laboratories worldwide. In the first decades of introducing bender elements for soil testing, in the 1980s and 1990s, the quality of the bender elements was a main research topic. After noticeable findings about wiring, shielding, and other design features, the focus of the research moved towards other factors, such as how to improve the quality of the test and how to interpret the results. The quality control of the bender element itself appears to have been neglected while they are partially manmade products and non-similarity happens in making them; as a result, the dynamic characteristics of the bender elements differ. The noisy, irregular signal detected in bender element tests is influenced by several factors including potential manufacturing anomalies. This study describes a simple approach to assess the quality of a bender element in the laboratory. Furthermore, it demonstrates a practical procedure for the estimation of the natural frequency and damping of a bender element.