# Research on the Structure of an Underground Irrigation Composite Pipe-Forming Device
## 5 Experimental Validation and Comparison  
In order to verify the validity of the simulation optimization results of the extrusion-forming parts and to compare and analyze the forming efficiency of the extruded composite pipe of the underground irrigation composite pipe-forming device before and after the optimization of the extrusion-forming parts, the test was carried out at the facilities of Moist Agricultural Equipment Co., Ltd., in Hebi City, Henan Province, China, using a constructed corn straw return machine. The main working parts of the corn straw return machine include straw collection, crushing, conveying, and trenching mechanisms, as well as an underground irrigation compound pipe-forming device. The parameters of the underground irrigation composite pipe-forming device were optimized; the diameter of the winch blade was 430 mm, the shaft diameter of the winch was 86 mm, and the winch pitch was 387 mm. The field operation of the test prototype is shown in Figure 8. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{1}{c}{**Combination of Structural Parameters of Underground**} & \multicolumn{1}{c}{**Measured Calculated Value**} & \multicolumn{1}{c}{**Normalized Value**} & \multicolumn{1}{c}{**Comprehensive Performance Indicators**} \\ \cline{2-6} \multicolumn{1}{c}{**Pipe-Forming Device**} & **Q** & **W** & **q\({}^{\prime}\)** & **w\({}^{\prime}\)** & **Indicatey** \\ \hline \(D_{1}\) & 1.26 & 180.49008 & 0.307317073 & \(-\)0.310766722 & 0.060083555 \\ \(D_{2}\) & 1.2 & 193.51952 & 0.292682927 & \(-\)0.333200732 & 0.042329463 \\ \(D_{3}\) & 1.64 & 206.78 & 0.4 & \(-\)0.356032546 & 0.097586982 \\ \hline \hline \end{tabular} Note: Q is the material output rate, Kg-s\({}^{-1}\); W is the power, kW; q\({}^{\prime}\) is the normalized material output rate; w\({}^{\prime}\) is the normalized power.  
\end{table} 
Table 3: Comprehensive performance calculations of test indicators. Figure 7: Comprehensive performance index values for the forming test device with different structural parameters. The test material was corn from the local test field, and the moisture content of the corn in the area was obtained at 25% by sampling the average values randomly for different areas. To ensure the effectiveness of the field test, a 2-m-wide and 10-m-long area was selected for the underground irrigation composite pipe-forming test. Before the test, the underground irrigation composite pipe-forming device was controlled at about 470 r/min by adjusting the tractor output shaft speed. With 1 m as the marker amount, a test distance of 6 m was chosen. The tractor works at a traction speed of 6.5 km/h. Under the tractor's traction, the whole machine started to operate in the field. According to the preliminary test, we obtained a composite pipe with an outer diameter of 100 mm and an inner diameter of 30 mm, and the composite pipe's forming density was not less than 1.30 g/cm\({}^{3}\), as qualified in [10]. When the whole machine operating distance reaches 1 m, the stopwatch records the operating time and the composite pipe length of 100 cm is weighed. A total of six sets of forming weight and forming time values for the composite pipe measuring 100 cm in length were recorded, and the forming density and forming rate were calculated. The test six was performed times to obtain the average value; the test results are shown in Table 4.  
The composite pipe had an outer diameter of 100 mm and an inner diameter of 30 mm obtained. It was a hollow pipe made of a mixture of straw, water, and soil extruded by an underground irrigation composite pipe-forming device. It had a uniform texture and a smooth inner wall. There were uniform tiny cracks distributed on the wall of the pipe,