The mechanical properties of round culm in Phyllostachys pubescens
[Objective]In order to promote the application of Phyllostachys pubescen in buildings,roads,bridges and geotechnical foundations,it is necessary to provide reliable use basis of P.pubescens components in engineering.Systematically elaborating the mechanical properties of P.pubescens is an important basic work for popularizing its structural materials.[Method]Taking P.pubescens as raw material,the longitudinal shear strength,compressive strength,tensile strength,ring stiffness and bending strength of P.pubescens were measured according to LY/T 2564-2015,and the corresponding load-displacement curves were analyzed.The bending strength specimens were selected for three-dimensional non-contact and high-precision full-field strain real-time monitoring.[Result]The shear strength,compressive strength,tensile strength,ring stiffness and bending strength of P.pubescens were 27.36 MPa,56.67 MPa,141.46 MPa,104.74 N/mm2 and 133.31 MPa;The shear bearing capacity,compressive bearing capacity and ring stiffness were positively correlated with the diameter,which was in the range of 70-90 mm,and the above bearing capacity increased with the increase of the diameter.The longitudinal shear strength,longitudinal compressive strength,ring stiffness and bending strength of the samples all showed obvious cracking or deformation during the experimental loading process,and then the bearing capacity was lost after continuous loading.DIC recorded that the displacement of P.pubescens when it reached the failure load gradually decreased from the lower part to the upper part,from 2.564 mm to 2.269 mm;The micro-strain in the lower part was-163.904×105,and the micro-strain in the upper part was 152.417×105.The structural failure showed that the upper compressive stress and the lower tensile stress increased at the same time and approximately the same.[Conclusion]Experiments show that the hollow P.pubescens has a high bearing capacity,and with the increase of the diameter of P.pubescens bearing capacity increased,from the load-displacement curve can be seen that P.pubescens has a certain degree of plastic deformation capacity,in the practical application of the destruction of the performance of a very good.
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