ABSTRACT

Driving forest machines on wet soils causes irreversible soil compaction, often associated with intensive rut formation and inaccessibility of wheeled forest machines for future forest operations. The German forestry equipment manufacturer FHS, Forsttechnik Handel & Service GmbH, engineered a forwarder, the Trac 81/11, equipped with conventional, well-proved bogie-axles embraced by a closed rubber track. At the center of the bogie-axle, four additional supportive rollers are placed to increase the load-carrying section between the tires of the bogie-axle. The study aimed to characterize the principle concept and the trafficability of the forwarder by analyzing the footprint area, the contact pressure, the rut formation on forest sites and the slippage during driving. Therefore, the effective contact area was measured on steel plates and rut formation was analyzed on a case study basis. Results showed that the supportive rollers increase the contact surface area by about 1/3. By this, a decrease of peak loads below the wheels and a more homogenous load distribution were observed. However, the contact surface area is still clearly divided into three parts; the area between the supportive rollers and the wheels does not take any load. Results of the rut formation were diverse: After 20 passes with 26,700 kg total mass, rut depth varied between 12.6 and 212.5 mm. Overall, the new undercarriage concept of FHS demonstrated a generally positive performance. The engineered forwarder contributes to reduce the environmental impact associated with log extraction.

摘要

在潮湿的土壤上驱动林业机械会导致不可逆的土壤压实，这通常与密集的车辙形成以及轮式林业机械无法用于未来的森林作业有关。德国林业设备制造商FHS（Forsttechnik Handel＆Service GmbH）设计了货运代理人Trac 81/11，配备了经过验证的传统转向架车轴，并由封闭的橡胶履带包围。在转向架车轴的中央，放置了四个额外的支撑滚轮，以增加转向架车轴轮胎之间的负载部分。该研究旨在通过分析足迹面积，接触压力，森林站点上的车辙形成以及行驶过程中的滑移来表征货运代理的基本概念和可运输性。所以，在钢板上测量有效接触面积，并以案例研究为基础分析车辙的形成。结果表明，支撑辊将接触表面积增加了约1/3。这样，观察到车轮下方的峰值载荷减小，并且载荷分布更加均匀。但是，接触表面积仍然清楚地分为三个部分：支撑辊和轮子之间的区域不会承受任何负载。车辙形成的结果是多种多样的：经过20次传球后，总重量为26,700公斤，车辙深度在12.6和212.5毫米之间变化。总体而言，FHS的新起落架概念表现出总体良好的表现。经过精心设计的货运代理有助于减少与原木提取有关的环境影响。结果表明，支撑辊将接触表面积增加了约1/3。这样，观察到车轮下方的峰值载荷减小，并且载荷分布更加均匀。但是，接触表面积仍然清楚地分为三个部分：支撑辊和轮子之间的区域不会承受任何负载。车辙形成的结果是多种多样的：经过20次传球后，总重量为26,700公斤，车辙深度在12.6和212.5毫米之间变化。总体而言，FHS的新起落架概念表现出总体良好的表现。经过精心设计的货运代理有助于减少与原木提取有关的环境影响。结果表明，支撑辊将接触表面积增加了约1/3。这样，观察到车轮下方的峰值载荷减小，并且载荷分布更加均匀。但是，接触表面积仍然清楚地分为三个部分：支撑辊和轮子之间的区域不会承受任何负载。车辙形成的结果是多种多样的：经过20次传球后，总重量为26,700公斤，车辙深度在12.6和212.5毫米之间变化。总体而言，FHS的新起落架概念表现出总体良好的表现。经过精心设计的货运代理有助于减少与原木提取有关的环境影响。接触表面积仍然清楚地分为三个部分；支撑辊和轮子之间的区域不会承受任何负载。车辙形成的结果是多种多样的：经过20次传球后，总重量为26,700公斤，车辙深度在12.6和212.5毫米之间变化。总体而言，FHS的新起落架概念表现出总体良好的表现。经过精心设计的货运代理有助于减少与原木提取有关的环境影响。接触表面积仍然清楚地分为三个部分；支撑辊和轮子之间的区域不会承受任何负载。车辙形成的结果是多种多样的：经过20次传球后，总重量为26,700公斤，车辙深度在12.6和212.5毫米之间变化。总体而言，FHS的新起落架概念表现出总体良好的表现。经过精心设计的货运代理有助于减少与原木提取有关的环境影响。