Measurements and Simulation of Compressive Behavior of Biodegradable Seedling Containers

Abstract

Highlights Compression tests were conducted on biodegradable containers with various conditions. The lateral loading reduced the compressive strength compared with the vertical loading. A model was developed using FEA to simulate the compressive behavior of the biocontainer. Model results showed similar ductile behaviors of the biocontainers with test results. The compressive strengths of wet biocontainers were below 20% of dry ones. Abstract. Biodegradable seedling containers (biocontainers) are becoming increasingly popular for use in transplanting and greenhouse applications. However, biocontainers have reduced mechanical strength when compared to plastic containers, often being damaged during the handling process. In this study, Canadian peat moss biocontainers were tested to study their compressive properties under different scenarios of various container sizes (small and large), moisture conditions (dry and wet), and orientation (vertical and lateral) relative to the loading direction. Also, simulations were performed using the Finite Element Analysis (FEA) for the selected scenario, focusing on the small container with two moisture conditions. The testing results showed that the force-displacement behavior of biocontainers varied dramatically with the orientation. In the lateral orientation, the biocontainers were able to carry loads while being largely deformed. However, the lateral orientation resulted in a reduced compressive strength of 21% compared with the vertical orientation. The moisture condition was found to be the second most dominant factor affecting the result. The compressive strength of the wet biocontainer was only 15.4%-19.6% of the dry ones. FEA simulation results showed similar ductile behaviors of the biocontainers under compression. Compared with the testing results, the relative errors of the simulated compressive strengths were 24.0% for the small, dry container and 9.89% for the small, wet one. FEA simulations were conducted with various Young’s Modulus values, revealing a logarithmic relationship with the container strength and deformation. The obtained knowledge of how the biocontainers react when subjected to compression provides insight to the failure mechanism of the container. The information is valuable for guiding the proper handling of biocontainers. Keywords: Biocontainer, Compression, FEA, Moisture condition, Property.