Testing base and testing of military vehicles at the 21st Research and Testing Institute of the Russian Federation Defense Ministry
Tests are a very complicated, capacious, multifaceted and continuously evolving (improving) process acting as the basic measure of product quality.
Presently, there is no exact definition of the notion «tests» with the official versions presented below failing to reflect in full the meaning thereof: under GOST16504, tests are experimental determination of the quantitative and/or qualitative characteristics of the properties of the tested item as the result of the effects thereon during operation or in simulation of the item and/or the effects with «determination» also meaning assessment and/or control; under ISO MEK 2, tests are a technical operation seeking to establish one or more characteristics of the given product, process or service in accordance with the existing procedure.
It is known that any newly created product requires control. As a rule, a product is improved (optimized) based on results of the tests at any level and may, in turn, require a finer tool for the subsequent more objective verification, etc.
So what are tests? First of all, these are a philosophic category that changes its «image» in time.
To get onto the notion of «tests», it seems to be reasonable to consider the stages of their origination and evolution (development) based on examples of MV models.
The Red Army acquired the first experience of testing motor vehicles after the establishment of the Scientific and Testing Tank-Automotive Test Range set up in 1931 by order № 22 of the USSR Revolutionary Military Council. The first tested models included the D8 armored vehicle, the Ford motorcar, YaK-10, NATI-2, Harley Davidson motorcycles and others. The growth in scopes of armored vehicle testing is evidenced by the fact that the manning structure of the test range changed seven times during an exclusively short period of 1931-1938 with the personnel number having grown from 23 to 390 by the second half of 1938. The prime task of the tests during that period was to assess serviceability of military materiel, including motor vehicles, and capability of these to negotiate natural obstacles. An important step in this work was also testing of separate assemblies, operating materials and lubricants.
An earlier period involved organizing tests of motor vehicles within the industry and at manufacturer sites. At that time, motor rallies were thought to be the most efficient way to check the quality of vehicles and, first of all, serviceability of these. One of the first and the biggest motor rallies with participation of the Russian AMO-F-15 trucks was held in 1925. It largely represented motor vehicles from foreign countries, including the USA, Germany, France, Czechoslovakia, Italy, Austria and Great Britain. 45 trucks and 79 motorcars took part in this rally for a distance of 4,724 km. One of the AMO-F-15 trucks (laterally a year after the first motor vehicle was turned out in November 1924) was among the rally winners.
The summer of 1933 saw an all-Russian 10,000 km testing motor rally on the route Moscow – Gorky – Kazan – Samara -Orenburg – Aktyubinsk – Tashkent – Kara-Kum – Kyzyl-Kum -Krasnovodsk – Baku – Tbilisi – Vladikavkaz – Rostov-on-Don -Kharkov – Moscow, in which 23 motor vehicles, including six GAZ-A cars, took part. Of these, the AMO-3 truck with a payload of 2.51 had the best functional qualities.
The first test work based on scientific principles began in the early 1930s after the establishment and formation of the Scientific Automotive Institute (NAMI) with its task being largely bench and laboratory tests of separate packages. Laboratory tests of full-scale motor vehicles began from the introduction of a drum test bench (Riddler bench). Road tests based on this institute were limited and used very simple procedures including determination of static characteristics (dimensions and weight) and runs of up to 100 km with determining the average speed and fuel consumption rates. Extensive studies based on the drum bench formed the basis for «Dynamic and Economic Studies of Motor Vehicles”, a spacious treatise byYe.A. Chudakov.
At the same time, more reliance began to be gradually placed on road and laboratory road tests due to the laboratory bench tests of motor vehicles lagging behind the requirements for their scopes and schedules. 1932 and 1933 saw the first «wear and reliability” running tests of the AMO-3, GAZ-A and GAZ-AA motor vehicles. These enabled development of recommendations on eliminating the limitations revealed.
As earlier, these tests were paralleled by planning and conduct of motor rallies.
Meanwhile, search for improved test methods continued. Of specific interest here can be the international competition tests conducted in the USSR in 1934 to try out foreign diesel engines installed in the ZIS-5 and Ya-5 motor vehicles (two models of each type). This was for the first time that the test program involved successive bench tests, laboratory road tests and a test run on the route Moscow – Kharkov – Rostov-on-Don – Ordzhonikidze -Tiflis and back, as well as disassembly and micrometering of the engine parts after the test completion. The tests were held by a commission chaired by Professor N.R. Brilling of the Moscow Higher Technical College named after N.E. Bauman. The test run included 13 motor vehicles from the Moscow car plant, 25 motor vehicles from the Yaroslavl car plant and one motor vehicle from the Gorky car plant. Only two of all diesel engines were of a domestic design. This was a breakthrough in the planning and development of methods for full-scale motor vehicle tests with regard for conditions of their conduct and assurance of comparability of results that, apart from specifically obtained matter on performance, wear of coupled parts and no-failure operation, formed the basis, primarily, for developing a regulatory framework of tests.
The Great Patriotic War brought about a dramatic change in the outlined plans for further development of the industry, construction of test ranges and improvement of testing methods.
The scope of the tasks set for the tests were minimized and solved as part of the runs with these not being planned but conducted as was objectively required. Foreign motor vehicles land-leased to the Soviet Union, most of which were assembled at plants in Iran, were delivered under their own power on two natural «test»> routes with one being Teheran – Resht – Astara – Baku -Tbilisi – Ordzhonikidze and the other being Teheran – Kazvin -Tabriz – Julfa – Nakhichevan – Yerevan – Tbilisi – Ordzhonikidze.
Most of the attention during the «runs» was given to detection of defects and elimination of these predominantly at the run destination. Rather a large number of defects was caused primarily by poor quality of assembly at the car assembly plants near the Iranian ports because of an insufficient professional level of workers (who were often illiterate) and a limited number of drivers with the required experience of «ferry tripping» motor vehicles for long distances. In nearly three years, out of 194,075 motor vehicles assembled at four US and two British car plants and at several car assembly stations at the Persian Gulf ports 184,112 were shipped to the Soviet Union. These included Studebakers, Chevrolets, Ford-6s, Dodge 3/4s and other motor vehicles.
A new stage in motor vehicle tests within the army began with the creation in March 1943 of a Special Experimental Workshop at the Technical Department of the Red Army’s Chief Motor Vehicle Directorate (GAVTU KA) that was converted in 1944, following a series of reorganizations, to the motor vehicle testing base of GAVTU KA headed at the time by Engineer Major G.P. Lyzo. In 1943-1945, these departments performed more than five hundred tests of largely foreign (land-leased) and captured motor vehicles, including assemblies, units, instrumentation of electrical components, tires, lubricants, fuels and others. This is exemplified below by materials of official reports on the actually performed tests kept to date in files.
1. Road tests of the Ford G8T motor vehicle (1943 model) to determine its technical data as compared to the 2G8T model (turned out in 1941) that had been redesigned. In accordance with the program, the basic service properties were characterized, including speed, fuel economy, braking, etc., as well as geometric passability parameters. The report describes in details the designs of the motor vehicles, their units and systems, including differences, based on comparing their characteristics. It also gives practical recommendations on their purposeful application with the army.
2. The 1944 comparative tests of the GAZ-63 and Chevrolet G-7107 motor vehicles for additional verification of the GAZ-63 strength and reliability after the first stage of the tests in the scope of 4,187 km. This was paralleled by measuring the fuel consumption and determining the average speed, as well as by determining the drawbar capacity. For the GAZ-63, the test roads used included asphalt (25 %) and cobble stone (14 %) roads, country roads (41 %) and driveways to the tests sites (20 %) with the percentage of these for the Chevrolet tests being respectively 5.6,18.5,30 and 55.9 % and the total run distance being respectively 3,551 and 3,000 km. The above data indicate that the scope and distribution of the run on these types of roads differed greatly for the models, which made it impossible to formulate the findings on these tests in rather an objective way.
3. The 1944 comparative tests of the all-wheel-drive Studebaker US6 motor vehicle (6×6), the ZIS-42 half-tracked serial truck, an upgrade of the ZIS-42 motor vehicle, the ZIS-AT-3i half-tracked truck tractor and the Studebaker US motor vehicle (6×4) to assess their combat characteristics, compare towing and operating properties for determining (specifying) applications for these and assessing comparatively the reliability (actually serviceability) of the models under different road conditions, including in towing artillery pieces.
In the postwar years, as experience was accumulated, the number of tested models was increasing and the range of the assessed parameters was expanding. As earlier, however, the results of the tests were largely subjective due to the absence of instrumentation and a poorly developed regulatory framework. All this was still to be created but primarily required training of personnel which took several decades.
Modern tests of motor vehicles are strictly controlled, based on dozens and hundreds of standards of different level and respective procedures, provided with sophisticated instrumentation, diagnostic equipment, a complex of test roads, artificial structures and skilled personnel. All this has largely helped to assure the fulfillment of the major metrological requirement, i.e. unity of tests with achieving the test results required in terms of accuracy, reliability and reproducibilty.
With the up-to-date system of tests, effective standards stipulate separate tests of pilot models and serial items at different stages of developing and commercializing motor vehicle models. Prototypes undergo preliminary (factory) and acceptance tests. A prototype can result from development of dummy models subjected to developmental (research) tests to optimize individual characteristics and search for rational designs of components. Depending on the level, acceptance tests can be governmental, intradepartmental and departmental.
The purpose of preliminary tests is to assess the quality level of models and find out if these are ready to be submitted for acceptance tests. The purpose of acceptance tests is to assess the compliance with requirements to combat characteristics and find out if the model can be adopted for service (delivery) and if it is reasonable to bring it into serial production.
For quality checks and acceptance of models, serial vehicles undergo acceptance, periodic and type tests immediately at manufacturer sites or at the customer test grounds with certification tests based on environmental and safety parameters conducted by a third person at the governmental level in accordance with the UNECE Rules, normally at dedicated testing centers (laboratories).
The objectives of periodic tests are to check the stability of the parameters under assessment as well as to evaluate reliability of models in the scope of warranty run and efficiency of the design and process alterations developed based on test results and the drawbacks detected during manufacture. The major purpose of type tests is to assess the efficiency and expediency of making changes to the serial model’s design, technology or formulation of materials.
Modern tests encompass a broad spectrum of checks based on the assessed parameters with part of these being included in the requirements of serial vehicles as binding for certification in accordance with the above UNECE Rules. All checks the program stipulates are included in laboratory, laboratory road and special tests to determine certain properties of MV models. As applied to military vehicles, the most important of these determine largely their preparedness for service and mobility of troops and detachments whose armaments and war materiel are mounted on (transported by) MVs. The most distinguished of these checks for separate properties are checks applying to speed, fuel saving and vibration properties, cross-country ability, stability and steerability, smoothness of travel, external and internal noise, operability, maintainability, recoverability (recovery capacity) and, specifically, reliability (no-failure operation), as well as to many other properties.
Testing procedures, special equipment of instrumental assessment of recorded parameters and instruments for their processing and representation of observation results have been developed to determine each characteristic and are improved continuously.
The types and the structure of the effective test system are shown on the diagram based on an example of MV model acceptance tests.
Let us consider some of the components in this system and their connections in more details. But to begin with, we will note that the most important factors that define the extent of completeness to which the tested model quality is assessed should include the parameters under assessment, their range and validity (soundness). Based on general principles, they should meet the following requirements. In particular, it is important to find out: to what extent of completeness, objective-ness and accuracy the adopted characteristics reflect any property; if theoretical grounds are sufficient for selection of characteristics and the potentiality of these being implemented practically using the available (existing) technology; to what extent the selected characteristics reflect the physical processes of the property under investigation; if it is possible to check, process (and analyze) and represent observation results in digital or digital printed form aboard the tested vehicle as such, including with the aid of a personal computer; to what extent the list of the adopted characteristics under assessment has been harmonized in costs of determining their quantitative values.
In other words, to what extent the selection of these or those characteristics and methods of their determination is justified, including with regard for metrological requirements.
At present time, they essentially try to select any characteristic normally with regard for the preset accuracy of its quantification result, selection of respective recorders and total cost.
Based on the adopted characteristics under characteristics, their quantification procedures are determined and metrological certification is carried out.
The other group of factors that define the comparability and reproducibility of test results includes test conditions, including road test conditions, with stability of parameters of these being extremely important for objective assessment of any model property.
This requirement is largely met by hard-surface roads with stable characteristics and artificial structure of various configurations and profiles. To develop this provision, Europe’s two largest test sites were created in the mid-1960s with one of these based near Dmitrov (the largest one in terms of area, length of test roads and number of special structures) and the other located near Bronnitsy (the largest test site in terms of special departments and the scope of the tasks solved).
Apart from standard measurements, e.g. during dynamometric road tests for the said laboratory road work, artificial structures on both tests sites enabled simultaneous development and introduction of accelerated and forced test methods both for separate units and vehicles as the whole. This forcing of loading on the vehicle design components was achieved by effects of enhanced loads from the support surface of special areas that did not exceed their maximum values in operation of motor vehicles under the conditions typical for these and their application at a higher path frequency.
A theory of methods for forced tests of motor vehicles has been developed by a team of specialists led by Professor N.N. Yatsenko and set out in a number of treatises, including «Fundamentals of Technologies of Range Tests and Certification of Motor Vehicles” by S.F. Bezverkhy and N.N. ^i&tsenko (Moscow, IPK «lzdatelstvo standartov», 1996,600 pp.). Further into the 1980s, studies however revealed an insufficient convergence of results in the tests conducted simultaneously under accelerated and normal test programs based on the list of defects (failures and damages) of engines and transmission units of all-wheel-drive motor vehicles. In this connection, the programs and procedures of accelerated tests on test sites were updated with earth roads of different state (predominantly worn-down and poor ones), including friable sand and virgin snow, included in the test road structure in addition to special sections. Artificial structures, specifically those on the Complex Test Course (CTC) of the Federal State Enterprise «21st Research and Testing Institute of the Russian Federation Defense Ministry”, such as a large-cobblestone section, wedge-shaped hills, a bumpy road, a slant-wave section, etc., are broadly used in forced tests of separate vehicle units (frame, cab, van bodies, container bodies, axle beams, springs, shock absorbers, fasteners of mechanisms and systems, etc.).
For the purpose of determining the potentials of motor vehicles through their major functional qualities and later on for assessing the efficiency of their application, tests are conducted on dynamo-metric roads to determine: the drawbar and speed properties expressing the drawbar capacity depending on the propeller and support surface engagement and speed, as well as to determine the maximum speed, acceleration time on the preset path and up to the preset speed and parameters of the «acceleration-rundown» speed characteristic parameters; braking properties for assessing largely the efficiency of working and standby brake systems through presetting the vehicle deceleration value as well as the brake response time; the fuel economy capacity through the fuel characteristic in a steady state with discretely preset speeds, as well as reference fuel consumption and integral characteristics – average fuel consumption on various types of roads and driving cycle (urban, thoroughfare, etc.); steerability and stability in conditions of rectilinear motion and in performing a number of maneuvers in «direct», “Steering wheel jerk», «shifting» and «going into curve» modes (large turning place tests) with assessing the limiting speed of the specified maneuver (for skidding or turning over); vibration loading on the driver workplace and smoothness of vehicle travel assessed through mean-root-square vibration accelerations in the direction of the coordinate axes X, Yand Z in the 1 /3-octave bands within a range of 0.7-90 Hz at steady discretely preset speeds on hard-surface roads (dynamometric road, worn out concrete highway and large-cobblestone section). Development of test methods for this property, especially as applied to MVs, still remains a task of utmost priority. The reason is that smoothness of travel shows signs of a multifunctional property and features a broad range of effects on forming the factors of other properties and, primarily, on the dynamic loading level for units and assemblies, braking properties, steerability and stability, speed qualities, etc., with regard for the fact that the extent of realizing these properties depends predominantly on the level of vibration loading on the driver workplace. It is simple to find out that only test estimates on the said types of roads (hard-surface) in conditions of a stationary ergodic micropro-file effect on the object have been tried out to date. At present time, the pending problem is to assess the said parameters in the most probable environment of using and operating MV models, particularly on earth roads of various condition (by their categories in accordance with OST 37.001.520).
The work in this direction has already been started and the indicators assessed for this property have been already found, including vibration dose, equivalent corrected value, peak factor and others. GOST RV «MVs. Indicators of Travel Smoothness for MVs and Methods of Their Determination” has been drafted. Currently, a pilot procedure has been developed as part of a research to define the said indicators. Instrumentation for their recording and means of processing and forms of representing observation results with a preset accuracy have also been developed.
Reliability, the second exclusively important property, also requires separate consideration. Reliability includes no-failure operation, endurance, maintainability and preservability and also depends on the conditions of tests.
As a matter of fact, to assess, for instance no-failure operation, tests require rather specific conditions as a preset scope of run and its distribution by particular types of roads: asphalt-concrete highway – 20 %; cobblestone road of even replacement – 30 %; earth road in a satisfactory condition – 30 %; worndown earth road -10 %; softened earth road after flooding, terrain, virgin snow, friable sand- 10%, which enabled to suggest the achievement of rather a high level of their reproducibility in terms of no-failure operation every time the test results were assessed. But this rather a delusive suggestion took many years to adopt.
It should be noted in this connection that no property shows such degree of uncertainty as the above one with this primarily depending on the following factors:
1. As there are no quantitative characteristics and indicators of test roads (earth ones in particular), a subjective estimate of their categories is always present (one type of roads in reports can be classified as another type in accordance with all results obtained on this).
2. A broad range of changes in road characteristics, depending on weather and climatic conditions, including the test period (from one day to several months), which hampers implementation of the test program in preset scopes by road types.
3. Methods of assessing reliability of test results only through mean-time-between-failures do not meet the above generic requirements to assessed indicators (does not take account of the list of defects, including damages, «weightiness» of each failure and many other).
A thorough and large-scale experimental research into motor vehicle motion modes in various road and ground conditions and natural and climatic zones that was launched at the Federal State Enterprise «21 st Research and Testing Institute of the Russian Federation Defense Ministry in the mid-1980s led to the development of a procedure to assess test roads through quantitative indicators defined in OST 37.001.520-96 «Categories of Test Roads. Parameters and Methods of Their Determination” and in patents for inventions.
Continued work of the same team of authors has led to the development (at a level of a range of inventions for the «method») of a scientific and technical basis for controlled (regulated) technology of run tests to assess reliability (no-failure operation, endurance and maintainability) of vehicles, including military vehicles, under ever varying road and natural and climatic conditions in assurance of the major metrological requirement with respect to «reproducibility» of test results. This is achieved through that, independently of accidentally occurring natural road and weather conditions, the programmed loading level (a new indicator) of the tested vehicles reaches its nominal value (through monitoring and adjusting this during tests). In addition, it is through this indicator that the frequency of maintenance and the residual service life are determined depending on changes in test conditions with reducing any test conditions to category 1 and so on.
The closing stage in creating the entire complex of regulatory technical documentation on running tests for assessment of no-failure operation was the development of a technique that lacked the said drawbacks. The developed complex is a kind of a leap in development of new testing technologies to assess reliability based on results of rated tests.
The process of test research makes a broad use of bench equipment, including such important components as weighing and tipover benches, a three-axle drum bench, a large climatic chamber, an engine test bench, a model study bench (SIM-36M) and many others.
Long-term plans stipulate development and upgrade of geometrical measurement benches, assessment of static stability, a single-axle drum bench, tests of suspensions, a hydrodynamic bench for study and tests of MVs, etc.