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Five geometrically similar bulldozer blades, ranging in width 6.45-77.2 in., were tested in four different soil types. Tests were run at low speed and a constant cutting depth equal to 20% of blade height. Horizontal and vertical soil forces, soil force moments, and travel distances were measured. An analysis of the test data is presented and a method of predicting the draft force of larger blades from tests on smaller scale models is proposed. Test equipment, instrumentation, and test technique are described.

A study to define accurately and discover new parameters of productivity for the contractor has resulted in a new design concept in off-highway trucks. This new concept has been first applied in the International Model 180 Payhauler, a rear dump vehicle of 45 ton rated capacity. The function and form criteria are discussed by components and systems in terms of the complete vehicle and on the job applications.

As the American farmer continues to substitute capital and technology for labor, his need for more powerful tractors will increase. Utilization of this increased power can be achieved by the use of tools with greater working widths, performance of several combined operations in one pass, and increasing the field speed at which the various operations are performed. This paper explores some of the advantages (and disadvantages) of high tractor field speeds, first from the farmer's viewpoint and second from the engineer's or manufacturer's viewpoint.

Past experience in the design of construction equipment has shown the importance of being able to assess as accurately as possible the predicted life of a machinery's structural components. A procedure is described wherein, through proper initial planning of tests, data may be obtained that will facilitate the prediction of future component designs. From the information secured, it becomes possible to graphically relate a component's stress-time history and thereby arrive at a suitable requirement for a new design.

Two high performance industrial machines, the 3400 and 3500 International industrial loader-backhoe, featuring a balanced system of loader integral frame tractor and backhoe design have been introduced to the market. These combinations with matched hydraulic systems optimize operator comfort with machine durability and productivity.

Certain roll over protective structures, ROPS, require resistance to the propagation of brittle fractures at low temperatures. It is demonstrated that the Charpy test is not suitable for characterizing crack propagation resistance. A drop weight test of thin wall tubular specimens was developed which uses a brittle crack starter weld. This test provides an indication of the temperature transition from low to high crack propagation resistance. Because of toughened heat affected zones which can occur in cold formed steel this test is reliable only for hot formed tubes. The temperature transition to high propagation resistance can be determined with precracked Charpy and Dynamic Tear Energy, DT, specimens applicable to cold or hot formed steel. A weld joint simulation specimen was developed to determine energy absorption capacity and low temperature fracture behavior of ROPS joint designs and material.