An Experimental Study on the Lateral Impact of Fully Clamped Mild Steel Pipes

Abstract

This report presents some experimental data that were recorded from 130 impact tests on mild steel pipes in two drop hammer rigs. The pipes were fully clamped across a span which was ten times the corresponding outside pipe diameters which lie between 22 and 324 mm. All of the pipes except five had wall thicknesses of 2 mm approximately and were impacted laterally by a rigid wedge indenter at the mid span, one-quarter span or near to a support. The impact velocities ranged up to 14 m/s and caused various failure modes. Some comparisons between two sets of experimental results indicate that the laws of geometrically similar scaling are almost satisfied over a scale range of approximately five.

Impact behaviour of pressurised pipelines

“…The variables π 6 and π 7 are identical for both data sets. Also presented in Figure 2 are the unpressurised series E test results with π 3 = 29 (R = 29 mm, H = 2 mm, 2L = 600 mm) reported in [2]. It is evident that the three sets of data are not too dissimilar when recognising the differences in the pipeline materials, experimental arrangements and geometrical parameters and when considering the inevitable scatter in tests of this nature.…”

“…It is evident that a catastrophic failure occurs at the clamped support for all of the pressurised test specimens. Moreover, this failure develops for π 2 < 28.0 when π 8 = 0.26 and 0.39, whereas (Table 1); ◊, failure at a clamped support (Table 1); , large ductile deformations [8]; ∆, local failure at the struck position [8]; , global failure at a support [8]; +, experimental results [2]. Empirical predictions for the specimens in Table 1: 1 and 2, Ellinas and Walker [11] with K = 150 and K = 300, respectively; 3, de Oliveira et al [12]; 4, Soreide and Amdahl [10].…”

“…Several empirical equations have been developed over the years for predicting the final permanent transverse displacements, or damage, of unpressurised pipelines, as noted in References [1,2,8]. The predictions of [10][11][12] are compared in [3] with the experimental data reported in [3].…”

“…Some early theoretical studies and experimental results on unpressurised ductile metal pipelines, which are subjected to local static and low-velocity impact loads, are reviewed in References [1][2][3]. In addition, Brown et al [4] reported on the behaviour of 300 mm diameter mild steel pipelines impacted with solid missiles having various nose shapes and travelling with speeds up to 14.1 m/s.…”

“…Experimental tests at low velocities up to about 13.6 m/s were reported in Reference [8] on pipelines pressurised by a compressible gas (nitrogen). The pipeline specimens were the same as one set of the unpressurised test pipelines in Reference [2]. A wedgeshaped impactor struck normal to the pipeline axis at the mid-span and one quarter span positions and caused permanent inelastic deformations of the pipelines.…”