RU2282840C1 - Impact test method - Google Patents

Abstract

FIELD: racket engineering.

SUBSTANCE: splitting units are subject to testing. Exploitation conditions of splitting are reproduced and parameters of impact are measured. Resistance strain gauges are mounted onto tested unit close to area subject to impact. Resistance strain gauges are calibrated by acting onto tested unit by standard calibration impulse loads. Value of pulse impact is judged from readings of resistance strain gauges and from calibration plot. Actual value of total impact impulse can be used when units split without making changes in structure and without using complicated stand equipment.

EFFECT: improved precision; improved reliability of operation.

2 dwg

Description

The present invention relates to rocket technology and can be used in testing products for impact loads arising between two complex large-sized structures when they are separated.

, не оговаривая величины максимального усилия Р и времени его воздействия. Для подтверждения выполнения требований ТЗ проводят ударные испытания с имитацией эксплуатационных нагрузок и измерением параметров удара. Если имитация нагрузок, действующих при разделении, не вызывает особых затруднений, то измерение параметров удара, в частности суммарного ударного импульса, связано с большими трудностями.In the process of separation of large-sized units (such as compartments, missile stages), collisions of the separated parts are possible, regulated by the requirements of the technical specifications (TOR). As a rule, in TK, the value of the total shock impulse is limited (as a generalized characteristic of the impact)

without specifying the magnitude of the maximum effort P and the time of its impact. To confirm compliance with the requirements of TK, shock tests are carried out with simulation of operational loads and measurement of impact parameters. If the simulation of the loads acting during separation does not cause any particular difficulties, then the measurement of impact parameters, in particular the total shock impulse, is associated with great difficulties.

There is a method of determining the total shock pulse by measuring the change in impact force over time by using a special braking device and a force sensor (see the book "Engineering methods for studying shock processes." Batuev GS, Golubkov Yu.V., Efremov AK , Fedosov A.A., Moscow, Mechanical Engineering, 1969, p. 120, 124, 125).

However, this method requires sophisticated testing equipment and is applicable in stand-alone tests, in which one of the colliding nodes is replaced by a braking device, i.e. measurement of impact parameters under normal conditions (with direct impact of the test nodes) in this way is impossible.

The technical result is achieved by the fact that in the method of impact testing of separable product nodes, including the reproduction of operating conditions of separation and measurement of impact parameters, strain gauges are installed on the test site near the zone subjected to impact and their calibration is carried out, acting on the test site with regulated calibrated pulse loads, and when tested according to the testimony of strain gauges and the calibration dependence, the magnitude of the shock pulse is judged.

Figure 1 presents a graph of the calibration dependence, figure 2 is an oscillogram for recording the readings of strain gauges.

, где I_n - измеренная (по показаниям тензорезисторов) величина ударного импульса (см. фиг.1).Indeed, if strain gages are installed on the test assembly (compartment) in the contact area upon impact, they will "respond" (react) to shock loads. If, prior to the test, the test assembly is loaded with known (regulated) values of shock pulses I _f , then we can construct the calibration dependence

where I _n is the measured (according to the testimony of the strain gages) value of the shock pulse (see figure 1).

Now, under shock tests under standard conditions, the actual value of the total shock pulse is determined by the value of the measured shock pulse I _n using the above calibration dependence.

The magnitude of the measured shock pulse I _n during calibration and shock tests is traditionally (see page 169 of the same source) is determined by the oscillogram of recording the readings of the strain gauges as the area of the figure S (see figure 2)

where ε is the strain gauge strain.

, где V - скорость подхода соударяющихся узлов друг к другу.Regulated calibrated shock pulses are realized using a pendulum ram, i.e. by deflecting a load of calibrated mass m, hanging on a cable, to a regulated height N to obtain the total shock impulse

where V is the speed of approach of colliding nodes to each other.

Thus, the proposed method of impact testing allows you to measure the actual value of the total shock pulse when separating nodes (compartments) without finalizing their design and without the use of complex bench equipment. This method has been successfully tested during the development of the separation system of one of the missile systems with a contact diameter of contacting surfaces of ~ 900 mm.

Claims (1)

The method of impact testing of separating product units, including reproducing the operating conditions of separation and measuring impact parameters, characterized in that strain gauges are installed on the test unit near the zone subjected to impact and calibrate them, acting on the test unit with regulated calibrated impulse loads, and, when tested, strain gauges and calibration dependencies judge the magnitude of the shock pulse.

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