Abstract: A flexible pipe end portion connection structure is provided. The flexible pipe end portion connection structure includes a flexible pipe body and a joint. The joint includes a first end and a second end opposite to each other and has a channel extending through the joint in a direction from the first end to the second end. An inner sidewall of the first end of the joint has a plurality of first stepped structures, and an inner diameter of a portion of the channel corresponding to the first stepped structure gradually decreases in the direction from the first end to the second end. At least a part of an end of the flexible pipe body is inserted into the first end of the joint to fit with the first stepped structure.

Abstract: Disclosed is an urban non-metallic pipeline leakage location method, the method comprise the following steps: determining whether leakage occurs in a pipeline through numerical simulation law analysis or a Markov chain-based flow analysis method; for a leaking pipeline, establishing an inverse-transient control equation for non-metallic pipeline gas leakage, and obtaining pressure and flow rate data of each measuring point in different periods of time through experiments and substituting the data into the control equation to analyze experimental data; and defining a nonlinear programming problem of an objective function with a least squares criterion, and applying a sequential quadratic programming method to minimize the objective function, so as to determine the size and position of the leakage.

Abstract: Disclosed is an urban non-metallic pipeline leakage location method, the method comprise the following steps: determining whether leakage occurs in a pipeline through numerical simulation law analysis or a Markov chain-based flow analysis method; for a leaking pipeline, establishing an inverse-transient control equation for non-metallic pipeline gas leakage, and obtaining pressure and flow rate data of each measuring point in different periods of time through experiments and substituting the data into the control equation to analyze experimental data; and defining a nonlinear programming problem of an objective function with a least squares criterion, and applying a sequential quadratic programming method to minimize the objective function, so as to determine the size and position of the leakage.