DE102011056350B4 - Falling mass collection system for a drop weight tester - Google Patents

Abstract

Falling mass collection system for a drop weight, comprising: - a collecting beam (5) or a bolt (8), and - an actuator (4), whereby a falling mass can be arranged so that it can hit an impact surface in free fall and the collecting beam (5) or the bolt (8) by the actuator (4) after a first contact of the falling mass with the impact surface and after a return of the falling mass, prevents renewed contact of the falling mass with the impact surface by the catching beam (5) through the actuator (4) is raised in such a way, or by the latch (8) being engaged by the actuator (4) in such a way that the falling mass is caught by the catching beam (5) or the latch (8) after jumping back above the impact surface, the actuator (4) in a first switching state does not hinder the fall of the falling mass on the impact surface and in a second switching state prevents the fall on the impact surface, the actuator (4) being selected from: an electric mechanical converter; a lifting magnet; a magnetic switch; a pyro actuator; an electro-hydraulic element; an electro-pneumatic element; an electrorheological element and characterized in that a change between the first and the second switching state of the actuator (4) takes place via a signal from a sensor and / or a timer.

Description

The invention is in the field of material testing, reliability testing and safety technology and relates in particular to test devices for dynamic stress testing of objects, compression test stands and crash test test stands.

Compression tests and dynamic crash tests for material testing under defined conditions of component load and stress can be carried out in test systems or devices for guided drop tests. With the help of a precisely positioned falling test object or falling weight, defined loading speeds or falling energies can be achieved. Measured deformations are used to create models for simulated loads and to design structural elements.

A large number of measurement methods are typically used to characterize the dynamic component load and stress. These include, for example, the measurement of path, speed and acceleration-time courses, as well as the measurement of the expansion and compression forces that occur during impact. Applicable measurement technology includes, for example, acceleration, strain and temperature sensors, load cells, high-speed video technology for digital image analysis, laser vibrometers for optical path and speed detection, digital short-range photogrammetry and strip projection methods for optical displacement and deformation measurement.

The meaningfulness of compression tests and crash tests depends on the precision of the initial load values determined in each case. The more the reliability of the calculations and extrapolations based on it depends on the error-free and reproducible test execution. In DE 10 2007 021 196 A1 describes an automatic braking and safety device for free fall systems with a recoiling drop basket. Pamphlet US 2011/0132069 A1 teaches a device for producing impressions in a structure, in particular a firing pin device. The pamphlet U.S. 5,457,984 A describes an internally cushioned, self-locking vertical drop-weight impact test device.

Previously known solutions are only partially satisfactory, in particular for larger falling masses or falling heights. So far, it has not been technically possible to allow the falling mass used to act on the test specimen only once on appropriately dimensioned drop test stands for guided drop tests. After an often unavoidable recoil or rebound of the falling mass after primary contact, a secondary impact of the falling mass on the impact area or the surface of the test object had to be accepted up to now.

Fair copy

This object is achieved by a falling mass collection system for a drop weight device according to claim 1, the use of a falling mass collection system according to claim 6 and a method according to claim 7. Further embodiments, modifications and improvements result from the following description and from the appended claims.

According to one embodiment, a test stand is proposed which comprises an impact surface and at least one actuator, wherein a falling mass can be arranged above the impact surface in such a way that it strikes the impact surface in free fall and that the at least one actuator makes contact after the falling mass has rebounded the falling mass with the impact surface prevented. After the deliberately brought about first contact of the falling mass with the impact surface and a return of the falling mass from the impact surface, the actuator prevents renewed contact of the falling mass with the impact surface.

This has the advantage that the deformation brought about during the first impact is not changed by a new impact after the jump back. The measured values and / or findings that can be recorded on the impact surface and / or the falling mass are solely due to the impulse of the first impact. Their use in mathematical models and simulations advantageously offers increased security of performed calculations, derived predictions and conclusions.

According to a further embodiment, a test stand is proposed, wherein the impact surface is arranged at a predetermined height and the actuator does not hinder the fall of the falling mass on the impact surface in a first switching state and absorbs the falling mass at or above the height of the impact surface in a second switching state and / or blocked and / or causes their interception and / or blocking.

This offers the advantage that the falling mass cannot hit the impact surface again after it has ricocheted off the impact surface. Deformations caused by the first impact are retained and are available for unadulterated evaluation.

According to a further embodiment, a test stand is proposed which also has a catch bar, a hook, a lock and / or comprises a bolt, wherein the collecting beam, the hook, the lock and / or the bolt is raised by the actuator so that the falling mass is caught and / or blocked after jumping back above the impact surface.

This has the advantage that the actuator used catches and holds the falling mass, for example via a catching beam, a hook or a lock or a bolt.

According to a further embodiment, a test stand is proposed which additionally comprises a catching bar, a hook, a lock and / or a bolt, which are each engaged by the actuator so that the falling mass is caught and / or blocked after jumping back above the impact surface.

This has the advantage that the actuator used does not immediately catch the falling mass and does not have to withstand the impulse of the falling mass, but a bar, a hook or a lock or a bolt catches and holds the falling mass.

According to a further embodiment, a test stand is proposed which is characterized in that a change between the first and the second switching state of the actuator takes place via a signal from a sensor and / or a timer.

Advantages of using a sensor result from the fact that the catching device is not triggered prematurely, but only after the actual impact and the intended first deformation of the impact surface and / or the falling mass. Advantages of using a timer result from the fact that, given the known dropping time and height of fall, the point in time of the impact can be easily predicted and the fall arrest device can thus be activated at the correct time.

A possible addition to the drop test stand described is an additional drop device that releases a drop mass with little delay. Advantages of an adapted throwing device are that a timer can be activated synchronously with the activation of the throwing device, which timer activates the collecting device or at least one actuator 4 that actuates it after a predetermined time.

According to a further embodiment, a test stand is proposed which is characterized in that the sensor is, for example, a proximity switch, a light barrier, or an ultrasonic sensor and / or the timer is activated synchronously with the activation of a release device.

This offers the advantage that the passing of the falling mass can be detected almost without delay and the activation of the actuator or the falling mass collection system can take place in good time.

According to a further embodiment, a test stand is proposed which further comprises at least one guide, a tail unit, a guide device and / or a guide track or a similar device with which, on which, over which and / or in which the falling mass is guided.

This has the advantage of controlling the return of the falling mass, for example. The falling mass cannot move sideways in the event of an impact, which, for example, increases the safety of the work to be carried out on the drop test stand and allows a targeted arrangement of the falling mass collection system.

According to a further embodiment, a test stand is proposed which further comprises a device for adjusting the height of the one-sided fixation of the actuator in relation to the height of the impact surface.

This offers the advantage of being able to adapt the falling mass collection system implemented with the aid of the actuator to test objects of different dimensions or height of the respective impact surface. The height adjustment can be made continuously or in discrete steps, for example.

According to a further embodiment, a test stand is proposed which is characterized in that the actuator is selected from: electromechanical converter; Lifting magnet; Magnetic switch; Pyro actuator; electrohydraulic element; electropneumatic element; electrorheological element.

Advantages of these embodiments result from the fact that the named actuators can be switched quickly and the operational reliability of a catching device, even with short fall and return paths.

According to a further embodiment, the use of an actuator in a drop weight tester or a drop test stand for catching and / or blocking a falling mass above an impact surface is proposed, the actuator preventing the falling mass from contacting the impact surface again after the falling mass has jumped back from the impact surface.

The advantages resulting therefrom have been mentioned above.

• - Bereitstellen einer Messvorrichtung zur Erfassung einer Messgröße, ausgewählt unter: Weg, Geschwindigkeit, Beschleunigung, Zeit, Dehnung, Stauchung, Verschiebung, Verformung, Temperatur, Kraft, Reflexion, Adsorption; - Bereitstellen eines Fallmassenauffangsystems umfassend ein einseitig fixiertes Stellglied, wobei das Stellglied in Abhängigkeit von einem Signal eines Sensors und/oder eines Zeitgebers aus einem ersten Schaltzustand, bei dem ein erstes Aufprallereignis kinetisch nicht beeinflusst wird, in einen zweiten Schaltzustand wechselt, der ein zweites Aufprallereignis nach einem Rücksprung der Fallmasse verhindert;
• - Freigeben einer Fallmasse durch Aktivieren der Abwurfvorrichtung und Bewegen der Fallmasse auf einem Weg, der durch den Abstand zwischen Abwurfvorrichtung und Aufprallfläche zum Zeitpunkt des Abwurfs vorgegeben ist, bis zum Aufprall auf der Aufprallfläche; und - Aktivieren des Fallmassenauffangsystems, wobei das Stellglied 4 aus dem ersten Schaltzustand in den zweiten Schaltzustand wechselt und den Weg verkürzt.

According to a further embodiment, a method for characterizing the dynamic component loading and / or component stress through the targeted induction of an impact event, comprising the steps of: is set to a predetermined value and / or is adjustable between the throwing device and the impact surface;

• - Providing a measuring device for recording a measured variable, selected from: path, speed, acceleration, time, elongation, compression, displacement, deformation, temperature, force, reflection, adsorption; - Provision of a falling mass collection system comprising an actuator fixed on one side, the actuator changing from a first switching state, in which a first impact event is not kinetically influenced, to a second switching state, which a second impact event, depending on a signal from a sensor and / or a timer prevented after a jump back of the falling mass;
• - Releasing a falling mass by activating the dropping device and moving the dropping mass on a path which is predetermined by the distance between the dropping device and the impact surface at the time of the dropping, until it hits the impact surface; and - activating the falling mass interception system, the actuator 4 changing from the first switching state to the second switching state and shortening the path.

The described method offers the advantage of a one-time deformation of a test object or an impact surface. This has advantages for the reliability of derived models and predictions made.

According to a further embodiment, a method is proposed which further comprises the step of: providing at least one catching bar, a hook and / or a lock, the catching bar, the hook and / or the catch being moved, raised and / or by at least one actuator is engaged and the falling mass catches, blocks and / or holds after jumping back above the impact surface.

This offers the advantages already mentioned for the corresponding device.

According to a further embodiment, a method is proposed, wherein the provision of the drop mechanism and / or the drop tower further comprises the provision of a guide rail, a tail unit, a guide device and / or a guide track, the falling mass on, in or along the guide rail, the Tail unit, the guide device, and / or the guideway can cover the way to impact.

This results in the already mentioned advantages of checking the return.

According to a further embodiment, a method is proposed in which when the falling mass collection system is activated, the path is reduced by an adjustable amount and / or the falling mass is caught, blocked and / or held above the impact surface.

Advantageously, the shortening of the path that the falling mass can follow after the falling mass has jumped back or ricocheted off the impact surface means that the falling mass cannot hit the impact surface a second time.

The embodiments described above can be combined with one another as desired.

• 1 zeigt ein Fallwerk mit einem Fallmassenauffangsystem;
• 2 zeigt Ergebnisse der Berechnung eines Auffangvorganges;
• 3 zeigt eine pneumatische Schaltung zur Steuerung elektropneumatischer Stellglieder;
• 4 zeigt eine Ausführungsform einer Sperre.

The accompanying drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention. The elements of the drawings are relative to one another and not necessarily to scale. The same reference numbers denote parts that are similar to one another:

• 1 shows a drop weight tester with a falling mass collection system;
• 2 shows results of the calculation of a trap;
• 3 shows a pneumatic circuit for controlling electropneumatic actuators;
• 4th Figure 3 shows one embodiment of a lock.

This in 1 The structure of the falling mass collection system shown consists of two portals 1 which are screwed onto a slab and which are each supported by two lateral supports 2 are stiffened against the slab. For a stepless height adjustment of the catching mechanism, pro
Portal with two spindle height adjustment devices each 3 are provided. These carry the traverses to accommodate the actuators 4th . Depending on the design, several actuators 4th hang on one of the four trusses. There are two catch bars on the underside of the actuators 5 mounted, each with one on a guide rail 7th guided collecting block 6th are connected. The two collecting blocks 6th are below the runner blocks that guide the falling mass, each in a guide rail 7th threaded. The two collecting blocks 6th hinder each lower runner blocks (not shown here) of the falling mass guidance after the end of the compression phase on the further journey in the direction of the test object or impact surface, when the falling mass falls back after a jump back.

The collection blocks are moved, for example, by an appropriately adapted actuator or an electromechanical, electropneumatic or magnetic drive. Alternatives to this are electrohydraulic, electrorheological or pyrotechnic actuator elements.

According to one embodiment, this can be done by impacting pneumatic actuators in the manner of fluidic muscles (Fluidic Muscle from Festo) with approximately 6 bar of compressed air. The fluidic muscles contract and raise the collecting blocks mounted on the collecting beam within approx. 100 ms by approx. 100 mm in the direction of the falling mass guidance system (lower runner blocks of the falling mass). In this way, the falling mass is caught before a secondary impact on the test object. Fluidic muscles equipped with silicone bodies can be used to reduce idle time, which enables travel distances of 100 mm in less than 100 ms after the application of pressure.

According to preferred embodiments, the supporting structure is adapted to the falling masses to be used. For example, after a pneumatic expansion of the system to 8 double strands of the fluidic muscles 4th the absorption of correspondingly larger falling masses, also possible up to and above 600 kg. The fluidic muscles work in the principle shown here 4th as drives for the quick catching of a falling mass in the case of drop weight devices 100 or drop test stands 100 and go into the loading slope themselves.

When selecting suitable actuators, the characteristic switching time (dead time) must be taken into account. The Fluidic Muscle mentioned 4th from FESTO (Germany) are characterized by a high positioning speed and a short dead time. These actuators contract when they are acted upon pneumatically and are faster than comparable pneumatic cylinders.

Embodiments

According to the in 1 The structural design of the test stand 100 shown for a guided drop test is connected to the used falling mass for guidance on two opposite sides with two runner blocks (not shown here) arranged one above the other, which in turn are on rails 7th to run. The two runner blocks attached to the falling mass on top of each other prevent the falling mass from tilting in the event of a fall or impact. The falling masses used can vary in shape and weight depending on the test requirements. The test setups in the test field between the guide rails are also variable 7th . For these reasons, a universally applicable collection point, independent of the shape of the falling mass and the type of experimental set-up, is available on the underside of the lower runner blocks that carry the falling mass.

By means of a collecting block that is also guided 6th that is on the same guide rail 7th of the test stand, on which the corresponding runner block is also running, the lower runner block of the falling mass guide is prevented from continuing to travel towards the impact surface or sample at the time of catching, and the falling mass is thus caught.

In order to avoid elastic shock conditions when catching, one-way aluminum-aluminum honeycomb panels with an adapted compressive strength, for example a compressive strength of 1.6-3.0 MPa, can be attached to the upper end faces of the collecting blocks, which deform plastically during the catching process and prevent a new jump back. Furthermore, the collecting blocks can be reinforced by a clasp made of aluminum, for example a material thickness of 15 mm.

In order to be able to estimate the requirements for the stroke and the actuating time of the actuators and to describe the requirements for the stroke and the actuating time of the required actuators, wood (spruce), falling mass 294 kg (h = 2.8 m) was used in a compression test Transverse strain hindrance (E = 8 kJ) investigated. The compression and the return parabola of the falling mass system (runner blocks) were determined.

In the case of the experimental setup described, you have "effectively" approx. 175 ms to absorb the falling weight before the secondary impact if the stroke is set at 100 mm, for example. The time taken for the process-controlled triggering of the catching mechanism after a clear return detection via the zero line (relative height of the impact surface) is already taken into account.

In addition to the switching time, the mass to be caught is another criterion for designing a suitable falling mass collection unit. The primary requirement here is that the falling mass collection unit must not influence the primary impact event through its use. As a result, the catching mechanism may only work when the falling mass is in the setback.

• - Rechen- und Signallaufzeit der elektronischen Steuerung (speicherprogrammierbare Steuerung - SPS);
• - Totzeit des pneumatischen Systems;
• - Verfahrzeit der Antriebe.

It should be noted that there is a period of time between the triggering and the action of the fall arrest mechanism that should not be neglected. This is made up of:

• - Computation and signal run time of the electronic control (programmable logic controller - PLC);
• - dead time of the pneumatic system;
• - Travel time of the drives.

Two basic triggering variants are proposed: the process-controlled triggering and the time-controlled triggering.

Process-controlled release.

In this variant, the release occurs only after the clear detection of the return of the falling mass. The return detection can be done with different sensors and a programmable logic controller (PLC). When a return jump is detected, the interception mechanism is started. The process-controlled release thus represents an operationally reliable release variant.

At least two sensors and a continuous switching flag that monitor the movement of the falling mass are required for clear return detection. Possible sensors are light barriers, ultrasonic sensors, inductive switches or similar components.

For example, inductive sensors of the type (Siemens 3RG4013-0CD00; SIMATIC PXI230) with a maximum switching distance of 5 mm can be used because of the play to be expected on the drop weight. Three inductive sensors S1, S2, S3 can also be used to increase the security of return detection. A programmable logic controller (PLC) records all signals and measures the transit times. A Siemens S7-300 with a CPU 313C was used for this, which guarantees a time resolution of 1 ms.

The Step7 and SCL software packages were used to program the PLC. A touch panel TP177 B-4 "from Siemens with the programming software WinCC flexible compact is used as input and output device.

The sensors are arranged vertically one above the other along the path covered by the switching flag. Sensor 1 (S1) is located via S2 and S2 via S3. The switching flag consists, for example, of a sheet steel 120 mm x 50 mm x 5 mm, which is attached to the side of the lower left runner block, for example, parallel to the guide rail cheek.

• - S11 - S1 rising edge (Primäre Kompressionsphase);
• - S21 -S2 rising edge (Primäre Kompressionsphase);
• - S22 -S2 falling edge (Rücksprungphase Wurf);
• - S12 - S1 falling edge (Rücksprungphase Wurf);
• - S13 - S1 rising edge (Rücksprungphase Fall); und
• - S23 - S2 rising edge (Rücksprungphase Fall).

The signal states to be recorded for the 2-sensor variant are:

• - S11 - S1 rising edge (primary compression phase);
• - S21 -S2 rising edge (primary compression phase);
• - S22 -S2 falling edge (throw back phase);
• - S12 - S1 falling edge (throw back phase);
• - S13 - S1 rising edge (return phase case); and
• - S23 - S2 rising edge (return phase case).

Timed release

A time-controlled triggering requires the exact knowledge of the expected sequence of movements of the falling mass during the test and would require several preliminary tests in order to be able to determine the scatter range of the start of the return sequence with sufficient accuracy. For example, after an inductive sensor has been occupied by the guiding system of the falling mass, a timer could be started during the fall, which starts the collecting mechanism after the respectively preset time period has elapsed. The time-controlled release variant offers the advantage of reacting to very short return times and very low return heights.

Collecting process

The results of the calculation of the entire collection process are in 2 compared to the actual path / time curve obtained from a high-speed video using point tracking. The upper curve shows the displacement / time curve of the falling mass and the runner block carrying the switching flag 11 . The curve below shows the path / time curve of the falling mass / runner block reconstructed with the aid of the video data. The third rising curve shows the travel path of the pneumatic muscles, which was also extracted with the help of the video data 4th Real time. The catch time and the catch height (catch point) result from the intersection of the path / time curves of the runner block and the pneumatic muscles. This diagram is important for the adjustment of the sensors and the height adjustment of the fall arrest system. Furthermore, the consideration of the path / time curves shows the feasibility of a process-controlled collection. In the modeling shown here, the setting times of hollow fluidic muscles were also used. In contrast, Fluidic Muscle with a silicone core have a dead time that is reduced to approx. 30 ms.

The calculated course is confirmed by the collection results of a practical measurement carried out with 3 inductive sensors. This means that rebound amplitudes from approx. 30 mm above the zero line can be absorbed in a process-controlled manner with the proposed test stand. For lower rebound amplitudes, the falling mass collection system can be operated time-controlled.

3 shows a double strand of the pneumatic part according to an exemplary embodiment for operating an electro-pneumatic actuator.
The symbols used for representation are the standard symbols used in accordance with ISO1219-1. Likewise, the numbers on the symbols are standard identifiers from pneumatics (ISO1219-1), for which a person skilled in the art does not need any further explanations. The unit marked 1Z1 and surrounded by a dashed line represents a compressed air maintenance unit.

According to a further embodiment, one possibility of absorbing heavier falling masses is made possible by a fundamental design change on the part of the load bearing. An exemplary implementation of a lock 8th that with the help of an actuator 4th to block the runner's block 11 a falling mass is indented in 4th shown.

For example, for falling masses> 600 kg, the falling mass can also be caught on the underside of the lower runner blocks. In this variant there is a lock driven by an actuator 8th indented. In 4A is the lock 8th disengaged, so does not hinder the free fall of the falling mass. In 4B the lock is shown in the engaged position. The engaged position is indicated by a stop 10 stabilized. In this position, an adapted dimensioning and material selection of the lock 8th , or a bolt and, if applicable, the load-bearing capacity of the stop 10 ensure reliable collection of the falling mass. The operation of such a lock 8th , a bolt or a hook can, as described, be engaged both process-controlled after return recognition and time-controlled after the output signal of a timer. Likewise, different actuators, for example one-sided rotatably mounted or fixed, can be used 4th of different types can be used.

• - Die zum Einsatz kommende Fallmasse trifft jeweils nur ein Mal auf einer zu prüfenden Komponente, Bauteil oder Probenmaterialie bzw. auf der untersuchten Aufprallfläche auf;
• - Ein Sekundäraufprall der Fallmasse auf die zu prüfenden Komponenten, Bauteile oder Probenmaterialien, respektive auf eine Aufprallfläche, kann durch eine automatisiert wirkende Fallmassenauffangeinheit verhindert werden;
• - Die Fallmassenauffangeinheit beeinflusst das primäre Aufprallereignis kinetisch nicht;
• - Der Fallprüfstand mit Fallmassenauffangeinheit ist für den Routineeinsatz zur Prüfung von Komponenten, Bauteilen oder Probenmaterialien mittels geführter Fallprüfung für Fallmassen bis etwa 600 kg geeignet und kann, bei entsprechender Auslegung wie beschrieben auch für den Einsatz größere Fallmassen angepasst werden.

Advantages of the proposed device and the proposed method are that a test stand with a falling mass collecting unit is provided which meets the following requirements:

• - The falling mass used only hits once on a component, part or sample material to be tested or on the impact surface examined;
• - A secondary impact of the falling mass on the components, parts or sample materials to be tested, or on an impact surface, can be prevented by an automated falling mass collection unit;
• - The falling mass collection unit does not kinetically influence the primary impact event;
• - The drop test stand with falling mass collection unit is suitable for routine use for testing components, parts or sample materials by means of a guided drop test for drop weights of up to approx. 600 kg and, with the appropriate design as described, can also be adapted for use with larger drop weights.

Fair copy

List of reference symbols

1 -

portal

2 -

lateral support

3 -

Spindle height adjustment device with traverse

4 -

Actuator, e.g. Fluidic-Muscle

5 -

Collecting beam

6 -

Collecting block

7 -

Guide rail

8th -

Lock

9 -

Bearing block

10 -

attack

11 -

Runner block (lower runner block of the falling mass)

Claims (10)

Falling mass collecting system for a drop weight, comprising: - a collecting beam (5) or a bolt (8), and - an actuator (4), wherein a falling mass can be arranged so that it can hit an impact surface in free fall and the collecting beam (5 ) or the bolt (8) by the actuator (4) after a first contact of the falling mass with the impact surface and after a return of the falling mass, prevents renewed contact of the falling mass with the impact surface by the catching beam (5) is raised by the actuator (4), or by the latch (8) being engaged by the actuator (4) in such a way that the falling mass after jumping back above the impact surface from the catching beam (5) or the latch (8 ) is caught, wherein the actuator (4) does not hinder the fall of the falling mass on the impact surface in a first switching state and prevents the fall on the impact surface in a second switching state, the actuator (4) being selected from: an electromechanical transducer; a lifting magnet; a magnetic switch; a pyro actuator; an electro-hydraulic element; an electro-pneumatic element; an electrorheological element and characterized in that a change between the first and the second switching state of the actuator (4) takes place via a signal from a sensor and / or a timer. Falling mass collection system according to Claim 1 , characterized in that the sensor is a light barrier, an ultrasonic sensor, and / or an inductive sensor and the timer is activated synchronously with the activation of a throwing device. Falling mass collection system according to Claim 1 or 2 , further comprising - at least one guide rail (7) for the falling mass. Falling mass collection system according to Claim 3 , the falling mass being guided with the guide rail (7) when it falls. Falling mass collection system according to Claim 1 to 4th , wherein the actuator (4) is rotatably mounted on one side or fixed on one side and the falling mass collection system further comprises: - a height adjustment device (3) for adjusting the height of the one-sided fixing in relation to the impact surface. Use of a falling mass collection system according to one of the Claims 1 to 5 in a drop weight tester or a drop test stand for catching and / or blocking a falling mass above an impact surface, the actuator (4) preventing contact of the falling mass with the impact surface after the falling mass has jumped back from the impact surface. Method for characterizing the dynamic component loading and / or component stress through the targeted induction of an impact event, comprising the steps: - Providing a drop weight and / or drop tower with an impact surface and a dropping device for dropping a falling mass, wherein the distance between the dropping device and the impact surface is set to a predetermined value and / or is adjustable, - Providing a measuring device for recording a measured variable, selected from: path, speed, acceleration, time, elongation, compression, displacement, deformation, temperature, force, reflection, adsorption; - Provision of a falling mass collection system, comprising: - a catch bar (5) or a bolt (8), and - An actuator (4) which is selected from an electromechanical converter, a lifting magnet, a magnetic switch, a pyro-actuator, an electrohydraulic element, an electropneumatic element or an electrorheological element; wherein the actuator (4) changes depending on a signal from a sensor and / or a timer from a first switching state, in which a first impact event is not kinetically influenced, to a second switching state, which prevents a second impact event after the falling mass has jumped back, by lifting the collecting beam (5) by the actuator (4) or by engaging the bolt (8) by the actuator (4) in such a way that the falling mass is above the impact surface of the collecting beam (5) or the bolt after it has rebounded (8) is caught; - Releasing the falling mass by activating the dropping device and moving the dropping mass, up to a first impact on the impact surface, on a path which is predetermined by the distance between the dropping device and the impact surface at the time of the dropping; - Activation of the falling mass interception system, the actuator (4) changing from the first switching state to the second switching state and preventing a second impact of the falling mass after the return jump. Procedure according to Claim 7 , further comprising: - providing a guide rail (7), wherein the falling mass on or in or along the guide rail (7) can cover the path up to the impact. Procedure according to Claim 7 or 8th , whereby when the falling mass interception system is activated, the path is reduced by an adjustable amount so that the falling mass cannot hit the impact surface a second time. Procedure according to Claim 7 to 9 , whereby the falling mass collection system is adapted for falling masses up to 600 kg and / or falling masses> 600 kg.

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