Results of computer modeling of a modular independent tubular suspension of a logging truck

The necessity of increasing the efficiency of timber trucks by improving the designs of their suspensions has been substantiated. The main disadvantages of traditional suspension structures used in modern logging trucks have been described. A promising design of a modular independent tubular torsion bar suspension for a logging truck has been proposed. The aim of the research consisted of two stages. At the first stage, a mathematical model for the functioning of the proposed torsion bar suspension has been developed. At the second stage, a computer program for a preliminary assessment of the effectiveness of the functioning of this suspension (when driving on an insufficiently equipped forest road) has been made. Time dependences of the angular positions of suspension arm fork and ends of the tubular torsion bars were obtained. The regularities of the influence of the movement speed, average height of irregularities, coefficient of dry friction on the relative spread of vertical loads and suspension indicators of vibration dispersions were revealed.

Operational Parameters of Logging Trucks Working in Mountainous Terrains of the Western Carpathians

Timber haulage is the last phase of the raw timber production process, necessary to transport timber to the customer. To improve the efficiency of logging truck operations, it is necessary to observe and assess several operational parameters through the electronic systems installed on the logging trucks. Measurements for this study were conducted for three logging truck types, which hauled 24,648 m3 of timber over 54,857 km and 1232 round trips. The RMC system was used for truck monitoring, equipped with a CAP04 capacitance sensor and a WGS 48 GPS module. The monitoring was continuous, lasting 27 to 74 weeks. Data acquired were evaluated via regression and correlation analyses and ANOVA. The results showed a moderately strong negative correlation between haulage productivity and haulage distance, ranging from r = −0.47 to r = −0.68. Simultaneously, a rather low efficiency of timber haulage was found for long-range haulage caused by legislation-based small utilization of the load-carrying capacity of the logging trucks. This showed in increased fuel consumption per production unit (2.01 Lm−3) as well as increased carbon emissions production (5.54 kg m−3).

Verification of timber carriers speed models movement depending on natural and production factors

One of the key production parameters of the forest transport process is the speed of movement of timber carriers when removing wood from the upper warehouse. This speed determines the maximum possible volume of prepared and exported wood. Many natural and industrial factors affect the speed of a timber truck. The speed of transport depends on the traffic conditions on the roads, which are significantly complicated by adverse weather events. Scientists have identified laws in changing the speed modes of moving vehicles based on practical observations of individual road sections. To identify the dependence of the speed of a logging truck on 31 factors under consideration, 162 observations were made on measurements of the speed of logging trucks in various natural and industrial conditions. Mathematical models have been developed for calculating the speed of a logging vehicle, taking into account natural and industrial factors. Verification of the obtained nonlinear and wave regression models is the goal of this article. To verify the models, an additional experiment was carried out to compare the calculated models of speed modes of timber carriers with the actual ones. During the experiment, we used data on the speed of a logging truck when transporting wood from the upper warehouse in the cutting area to the raw material warehouse of a wood processing enterprise on the territory of the Yenisei forest district of the Krasnoyarsk territory. The logging road was divided into six sections, each of which was divided into elementary sections by slopes. At each section, the parameters that affect the speed of the timber carrier were determined using previously identified multi-factor equations, and the estimated time of cargo delivery by the timber carrier to the destination was obtained. Comparing the actual travel time with the calculated one based on previously identified equations for a timber truck with cargo on the way from the upper warehouse to the point of wood delivery, it was found that the estimated time of cargo delivery coincides with the actual one with an error of 7 %, and this is an acceptable norm(less than 30 %) for technological processes. Thus, the obtained results of testing multi-factor models can be considered reliable.

Determination of the Safest Route for Logging Trucks Based on Road Types and Conditions

Hauling of wood-based forest products is a complex problem that requires evaluation of many alternative routes. Forest transportation has been generally done by using logging trucks with high carrying capacity. Logging truck driving is one of the dangerous occupations in forestry, particularly in Turkey, where forest lands are mostly located in mountainous regions with steep slopes. The safety risk of truck driving mainly depends on the road standards and conditions. The majority of the forest roads in Turkey have low standards that limit the maneuverability of logging trucks. In such conditions, forest transportation should be planned by considering not only transportation costs but also the safety of logging truck driving. In this study, the GIS-based network analysis method was used to develop the optimum transportation plans for two scenarios. In the first scenario, an optimum plan that minimized the total transportation cost was developed, while a transportation plan that ensured the safest logging truck driving was optimized in the second scenario. A safety score was assigned to each road section based on the road type (asphalt, gravel, forest road) and road conditions (good, medium, poor). In the study area, located in the city of Bursa in Turkey, there were three forest depots and five landings. The results indicated that the transportation cost increased by 15.76% when the safety of logging truck driving was prioritized. In this scenario, forest products from three landings were transported to different depots, compared to the first scenario.

Addressing Occupational Ergonomics Issues in Indonesian Forestry

This study addresses occupational ergonomics issues in Indonesian forestry (work conditions, workers' characteristics, occupational safety, occupational health, and job satisfaction) to acquire a comprehensive perspective in understanding the actual problems facing the operations. Direct observation, interview, questionnaires, and secondary data analyses were carried out to acquire all of the required information. A total of 191 frontline forestry workers (chainsaw operators, helpers, manual hauling workers, skidder/tractor operators, logging truck drivers, and nursery workers) participated in this study. The study shows that various techniques of forest operations (labor-intensive to semi-mechanized systems) have been applied in Indonesian plantation forests, both short and long-rotation, as well as in natural forest management. Most of the workers were non-permanent workers, who receive a low wage, work under a straight piecework system, have a high dependency on the forestry work to make a living, and exhibit poor comprehension of the concept of hazard control. The fatality rate was recorded as 1.3 deaths/106 m3 log, but this may be even higher as this rate only represents data taken from formal forestry workers. An intense physical dimension of fatigue occurs among workers involved in forest operations, with the highest prevalence of musculoskeletal disorders in the upper back, lower back, neck, shoulders, and arms. This study reveals eight variables that influenced job satisfaction, i.e., wage, type of contract, accessibility, health services, living facilities, work equipment, training, and social facilities.

Developing Methods for Truck Route Selection and Cost Modeling in Steeper Topographies

Payment tariffs for logging truck transport in Nordic countries are typically based on the loaded transport distance. Local tariffs often provide a good representation of the mean cost, however, as variation in topography and the transport environment increases; loaded distance alone represents the actual cost poorly. In addition, routes with increasing curvature also constitute more frequent braking and acceleration cycles. Moreover, driving in such topographical environments during the winter raises additional safety and operator stress issues. This study examines the situation in Norway where logging truck routes often start in mountainous regions. It tests the applicability of a route-generation system developed in Sweden and determines if it can be adopted in Norway. The case study is based on 30 detailed routes from each country, reported and analyzed by their respective transport managers. Based on typical local tariffs, the results show the route-specific variation in costs and profit margins associated with the varying transport environments. A framework for classifying transport environments is proposed as a basis for tariff agreements that better represent the actual transport cost. This increases fairness and supports economic sustainability for transporters.