Strength Classification of Wooden Chairs under Cyclic Loads Based on an Experimental Study

This study aimed to assess the cyclic load capacity of wooden chairs and subsequently categorize them based on their performance. A diverse selection of chair models was randomly procured from commercial markets. These chairs underwent performance testing, utilizing the cyclic stepped increasing loading method, with adherence to the standards set forth by the American Library Association Technology Reports (ALA). The study evaluated 315 chairs, encompassing 21 chair models. Each chair model underwent five replications of testing across three different loading directions. The resulting dataset of numerical values was subjected to statistical analyses, facilitating the categorization of chairs based on their strength under cyclic loads. Notably, the study revealed substantial variations in the load capacity among different chair models. As a consequence of this investigation, the study established acceptable design load thresholds. For instance, concerning front-to-back loading, it was determined that the chairs with cyclic load capacities ranging from 932 to 1449 N fell within the category of low-strength, between 1450 and 1968 N were classified as medium-strength (suitable for domestic use), and the chairs with cyclic load capacities exceeding 1968 N were considered to possess high strength (intended for hotel lobbies, restaurants, libraries, etc.). Similarly, for back-to-front loading performance, the study identified the chairs with cyclic load capacities between 625 and 895 N as low-strength, 896 and 1167 N as medium-strength, and the chairs with loads surpassing 1168 N as high-strength. The performance thresholds for side thrust loads were as follows: low-strength encompassed the cyclic load capacities ranging from 649 to 934 N, medium-strength spanned the cyclic load capacities between 935 and 1221 N, and high-strength entailed 1222 N and above. Notably, the classification devised in this study is closely aligned with the widely accepted and internationally recognized ALA specification. This strong consistency with global standards reinforces the reliability and applicability of the classification system developed in this research. In conclusion, this study enhances understanding of wooden chair strength performance and offers practical insights that lead to higher-quality products and improved consumer satisfaction. Its recommendations can potentially drive positive change within the industry and benefit manufacturers and consumers.