Field of the Invention The present invention relates to an apparatus and method for shock testing live ordnance or other items required to meet a shock specification.

Background to the Invention

After manufacture and before being accepted into service, new military ordnance is transported via a variety of delivery means, for example ships, trains, aircraft and road trucks, to its final point of use. Live ordnance and explosive materials have to undergo rigorous testing to ensure that they are safe for storage and transportation through normal handling means and while being used by military forces. Qualification of the performance of ordnance against shock arising, for example from transportation, or from mechanical shock caused by hostile act against the storage and transportation platforms, self-shock from launch conditions and military action is required to allow weapons to be embarked.

Live ordnance presents particular difficulties as the explosion of the item under test would destroy the test rig and surrounding structure. Currently, ordnance may be tested using a simple drop of the ordnance from a prescribed height or by using shaker systems to synthesize the shock pulse into a characteristic shaker excitation. Ordnance may also be tested as an 'All Up Round' or may be tested at component level in cases for example, where an item of ordnance has a warhead, and a rocket motor with fuel.

Commercial shock test machines normally capable of testing to transport, storage and in-use shock levels are expensive, do not exist on explosively licensed test ranges, and even if they did, would likely require to be installed in a building with services supporting them. The consequences therefore of an ordnance test resulting in an explosive event are that the facility would be critically damaged. It is also the case that all types of ordnance may during peace or wartime be transported by sea. In this case the transporting vessel may be subjected to underwater explosive loading, a phenomena which is termed "UNDEX". While the standard drop test method does impart an impulse to an item of ordnance this test cannot sufficiently match the exigencies and frequency content of UNDEX loading.

Summary of the Invention

In one aspect of the present invention there is provided a shock testing apparatus comprising:

an impact table for supporting an object to be tested;

a base structure;

an impact member support structure;

one or more impact members;

wherein the or each impact member is pivotally mountable to the impact member support structure at a location above the impact table by means of a swing arm; and

wherein the impact table is movably mountable upon the base structure; wherein motion of the impact table relative the base structure upon impact of the one or more impact members is damped by one or more damping members located intermediate said impact table and the base structure.

Optionally, the one or more damping members located intermediate the impact table and the base structure are connected at one end to the impact table, with their respective opposing free end(s) being movable towards and arranged to slidably abut against reaction structure(s) provided on the base structure.

Advantageously, the impact member or members of the shock testing apparatus deliver an acceleration pulse to the impact table and thus an object being tested, and the damping members provide a deceleration pulse to the article being tested. Optionally, the one or more damping members located intermediate the impact table and base structure are connected to the impact table via one or more intermediate members or support structures to which the impact table is affixed. Optionally, the impact table is connected to the base structure by variable spring- dampers and/or sliding connections to allow the shock pulse to be shaped by alteration of the spring stiffness and allowable stroke of the dampers.

In embodiments, the shock testing apparatus comprises at least two impact members.

Optionally, the impact table is movably mountable upon the base structure to allow movement in a substantially horizontal plane. The horizontal plane is that plane which is parallel to the base structure when placed on a surface in use. Optionally, the impact table is movably mountable upon the base structure by means of rollers or ball bearing supports.

Optionally the impact table is slidably mountable to the base structure. Optionally, the impact table is movable in transverse and longitudinal directions with respect to the base structure.

Optionally, the impact table comprises a first support surface and a second support surface, wherein the first and second support surfaces define a bed portion and a back stop, respectively.

Optionally, the second support surface is disposed towards a side edge of the first support surface and extends substantially orthogonally therefrom. Optionally, the first support surface of the impact table is arranged substantially parallel with respect to the base structure when mounted thereon. Optionally, the first and second support surface are elongate members each having opposing elongate side edges and opposing end edges.

Optionally, the impact table is provided with impactor plates at the locations of impact of the impact members.

Optionally, the impactor plates are sacrificial and replaceable.

Optionally, the impactor plates may be provided with one or more resilient coverings.

Variation of the properties of the resilient coverings allow the shock pulse imparted to the impact table to be shaped by alteration of rise-time of the response pulse of the impact table.

Optionally, there are provided a plurality of impactor plates disposed along one or both side edges of the first support surface, each impactor plate being adapted to engage with an impact member of the apparatus.

Optionally, the impact table further comprises an impactor plate disposed along one end edge of the first support surface.

Optionally, the shock testing apparatus comprises up to five impact members. Optionally, the shock testing apparatus comprises more than five impact members.

Optionally, the number of impact members used may be varied according to the article to be tested. For example, fewer impact members may be used where the article to be tested is of reduced size. Optionally, each impact member is of solid steel construction.

Optionally, each impact member may be raised to varying heights by raising mechanism. Optionally, the impact members may be coupled together by a locking means to ensure simultaneous impact or may be released separately in a deliberately phased manner to generate a variable shock input pulse.

Optionally, the energy of the impact induced in the impact table can be varied by varying the number of impact members engaged, their release height and the mass of the impact members.

Optionally, an indicator provided on the swing arms provides an indication of the drop height of the impact member(s) and thus confirmation for an operator that the drop height for the swing arm is correct for each and every swing arm. Optionally, the impact members are released by triggering a remotely operated release mechanism.

Optionally, the remotely operated release mechanism is a wired system. Optionally, the impact table is of steel construction.

Optionally, the impact table is formed from a plurality of separate but rigidly interconnected table elements to allow testing of articles of excessive length.

Optionally, the impact table is connected to the base structure by variable spring- dampers and/or sliding connections to allow the shock pulse to be shaped by alteration of the spring stiffness and allowable stroke of the dampers.

Optionally, the shock testing apparatus further comprises one or more data capture means, such as but not limited to: high-speed cameras; strain gauges; accelerometers.

Optionally, the base structure has a footprint that corresponds to the footprint of a standard ISO container unit.

Optionally, the base structure is nominally 6.06 m in overall length and 2.44 m in overall width. In this way, the base structure has the footprint of a standard 20 feet (ft) ISO container unit. Optionally, the apparatus further comprises removable side and rear walls and a top covering, the removable side and end walls adapted to upstand from the base structure such that the apparatus is convertible from a containerised transport configuration to an ordnance test configuration.

In another aspect of the invention there is provided an ordnance test system comprising a shock testing apparatus convertible between a containerised transport configuration and an ordnance test configuration, and a separate associated storage and remote control and instrumentation collection centre container.

Optionally, the containerised shock testing apparatus and associated storage and remote control and instrumentation collection centre container are provided in the form of ISO containers. Optionally, the ISO container format is 20 feet (ft). In this way, the containerised shock testing apparatus and the associated storage and remote control and instrumentation collection centre container can be transported together, for example on the bed of a standard 40 feet (ft) trailer.

In another aspect of the invention there is provided a method of shock testing an item of ordnance, the method comprising the steps of: providing a shock testing apparatus at a test location; mounting an item of ordnance onto an impact table of said shock testing apparatus; and impacting the impact table with one or more impact members of said shock testing apparatus. Optionally, the method of shock testing an item of ordnance, comprises the intermediate steps of: transporting the shock testing apparatus to the test location; placing the shock testing apparatus onto a suitable surface; and converting the apparatus from its containerised transport configuration to its an ordnance testing configuration.

The various aspects of the present invention can be practiced alone or in combination with one or more of the other aspects, as will be appreciated by those skilled in the relevant arts. The various aspects of the invention can optionally be provided in combination with one or more of the optional features of the other aspects of the invention. Also, optional features described in relation to one aspect can typically be combined alone or together with other features in different aspects of the invention. Any subject matter described in this specification can be combined with any other subject matter in the specification to form a novel combination.

Various aspects of the invention will now be described in detail with reference to the accompanying figures. Still other aspects, features, and advantages of the present invention are readily apparent from the entire description thereof, including the figures, which illustrates a number of exemplary aspects and implementations. The invention is also capable of other and different examples and aspects, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, each example herein should be understood to have broad application, and is meant to illustrate one possible way of carrying out the invention, without intending to suggest that the scope of this disclosure, including the claims, is limited to that example. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. In particular, unless otherwise stated, dimensions and numerical values included herein are presented as examples illustrating one possible aspect of the claimed subject matter, without limiting the disclosure to the particular dimensions or values recited. All numerical values in this disclosure are understood as being modified by "about". All singular forms of elements, or any other components described herein are understood to include plural forms thereof and vice versa.

Language such as "including", "comprising", "having", "containing", or "involving" and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Thus, throughout the specification and claims unless the context requires otherwise, the word "comprise" or variations thereof such as "comprises" or "comprising" will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention.

In this disclosure, whenever a composition, an element or a group of elements is preceded with the transitional phrase "comprising", it is understood that we also contemplate the same composition, element or group of elements with transitional phrases "consisting essentially of", "consisting", "selected from the group of consisting of", "including", or "is" preceding the recitation of the composition, element or group of elements and vice versa. In this disclosure, the words "typically" or "optionally" are to be understood as being intended to indicate optional or non- essential features of the invention which are present in certain examples but which can be omitted in others without departing from the scope of the invention.

Any references to directional and positional descriptions such as upper and lower and directions e.g. "up", "down", "horizontal" etc. are to be interpreted by a skilled reader in the context of the examples described to refer to the orientation of features shown in the drawings, and are not to be interpreted as limiting the invention to the literal interpretation of the term, but instead should be as understood by the skilled addressee. Brief Description of the Drawings

In the following drawings:

Figure 1 a is a schematic perspective front view of a first configuration of shock testing apparatus in accordance with the invention;

Figure 1 b is a schematic perspective front view of a first configuration of shock testing apparatus showing an object to be tested; Figure 2 is a schematic perspective rear view of the shock testing apparatus shown Figure 1 a;

Figure 3 is a schematic perspective front view of a second configuration of shock testing apparatus in accordance with the invention;

Figure 4 is a schematic perspective rear view the second configuration shock testing apparatus shown Figure 3; Figure 5 is a schematic perspective front view of the shock testing apparatus having an impact table comprising a number of impact table sections;

Figure 6 is a detailed view of an impactor plate and associated coverings in accordance with the invention;

Figure 7 is a schematic view of an impactor height indicator of the shock testing apparatus;

Figure 8 is a schematic perspective view of the shock testing apparatus in a containerised format;

Figure 9 is a schematic perspective view of a storage and remote control and instrumentation collection centre container associated with the shock testing apparatus; and

Figure 10 is a schematic perspective view of a shock testing apparatus in a partially disassembled format susceptible for containerisation.

Detailed Description

With reference to Figures 1 a to 4, in one aspect of the invention there is shown of shock testing apparatus 1 comprising an impact table 2 for supporting an object to be tested 10 (Figure 1 a); a base structure 3; and an impact member support structure 4 which supports a plurality of impact members 5.

The impact member support structure 4 is demountably attachable to the base structure 3 using bolted flanges 41 (Figure 1a) to maintain structural continuity between said structures. Impact member support structure may be arranged as an A-frame.

With reference to Figure 1 a and Figures 2 to 4, the impact table 2 preferably comprises a first support surface 21 and a second support surface 22. In one arrangement, the first 21 and second 22 support surface are elongate members each having opposing elongate side edges and opposing end edges. The second support surface 22 is disposed towards one elongate side edge of the first support surface 21 and extends substantially orthogonally therefrom such that the first 21 and second 22 support surfaces define a bed portion and a back stop of the impact table, respectively. As shown in Figure 2, a plurality of impactor plates 23 are disposed along one elongate side edge of the first support surface and optionally along one end edge of the of first support surface 21 , each impactor plate 23 being adapted to engage with an impact member 5 of the apparatus which strikes said impact table 2 in use.

Impactor plates 23 may be provided as sacrificial and replaceable parts. In this way, impactor plates of different thicknesses may be used to help achieve synchronicity of the impact of the impact members 5 with the impactor plates 23 of the impact table.

As shown in Figure 1 b, a test object 10 is rigidly attached to the impact table 2 by a suitable attachment mechanism, for example, but not limited to retaining straps, bands, clamps or collars 1 1 , designed to the replicate in testing the real- life constraints experienced by the object. The impact member support structure 4 supports a plurality of impact members 5, each impact member 5 being pivotally mountable to the impact member support structure 4 at a location above the impact table 2 by means of a swing arm or arms 51. Two or more impact members may be connected to the impact member support structure 4 about a common pivot arm. Preferably, impact members 5 are of solid construction and made from steel. Each individual impact member 5 and its swing arm(s) 51 form part of an impactor sub-system further comprising a raising means 56 (Figure 1 b) to raise the impact members 5 to a predetermined height above the impact table 2, and a release means 57 (Figure 1 b) to allow the impact member 5 to swing in a downward trajectory to impact the impact table 2 at an impactor plate 23 to impart a shock to the object 10 to be tested. The raising means 56 may comprise any suitable raising mechanism, for example, but not limited to, manually operated, motorised, pneumatic, pulley driven, or hydraulic motors. The raising means 56 may be pivoted from an operational position as shown in Figure 1 b, to a stowed position as shown in Figure 10.

As shown in Figure 7, an indicator 58 provided on the swing arms 51 provides an indication of the drop height of the impact member(s) 5 and thus confirmation for an operator that the drop height for the swing arm is correct for each swing arm.

While Figures 1 a to 5 illustrate embodiments of a shock testing apparatus comprising or accommodating five impact members/impactor subsystems arranged along the length of the apparatus, it will be appreciated that in accordance with the invention the apparatus may comprise one impact member, and which may be arranged at one or other side of the impact table.

For purposes of clarity, Figures 1 a, 1 b and 2 show only two impact members 5 provided along the length of the shock testing apparatus, whereas Figures 3 and 4 show five impact members 5 arranged along the length of the apparatus and a further impact member 5A and associated impact member support structure 4A of an optional arrangement located across the width of the apparatus at one end and adapted to strike an end edge of the impact table 2 to impart a longitudinal shock input to an object being tested. With reference to Figure 2, an optional locking mechanism 55 acting on the respective swing arms 51 of each impact member 5 enables impact members to be coupled together to permit simultaneous or synchronised release and hence simultaneous impact of the impact members with the impact table, or to effect separate, phased release of the impact members 5 to generate a variable shock input pulse to the impact table 2. Control over the raising and subsequent release of impact members 5 is remotely controllable by an operator located at a safe distance from the shock testing apparatus 1 , for example in a remote control and instrumentation collection centre container 60 (Figure 9) as described below .

Impact table 2 is mounted to the base structure 3 such that it can move laterally and/or longitudinally in response to an impact or impacts from one or more impact members 5, 5A. Thus the impact table 2 is movable in transverse and longitudinal directions. In one arrangement, the impact table 2 is slidably mounted to the base structure 3. To constrain and control the motion of the impact table 2 upon impact by an impact member or members 5, 5A, there is provided a plurality of dampers 6 which are located between said impact table 2 and the base structure 3. The damping members 6 may be arranged in pairs as shown in the figures. The damping members 6 are connected at one end to the impact table, with their opposing free end being adapted to move towards and slidably abut against a reaction structure 61 provided on said base structure 3 upon impact by one or more impact members. Thus the free ends of dampers 6 are not fixed to the reaction structures 61 , but rather are spaced apart from said reaction structures and are capable of contacting them, and sliding along or against them. In this way, interference of one or more dampers with one or more other dampers in use is mitigated.

Slidable abutment of each damping member 6 to the respective reaction structures 61 may be effected by an abutment plate 62. The ends of the damping members 6 that are connected to the impact table 2 may connected direct to the impact table or may connect via or via an intermediate member or support structure to which the impact table 2 is affixed in turn. In the latter case, a two or more impact tables 2a, 2b, 2c, having different lengths can readily be affixed to the apparatus in order to specifically accommodate different lengths of objects to be tested as shown in Figure 5.

Each damping member 6, or pair of damping members 6, is associated with an opposing impactor plate 23 located at an opposite side of the impact table 2 in use. The damping members 6 preferably comprise adjustable spring and/or or piston dampers. Through alteration of the spring stiffness and /or stroke of the damping members the shock pulse imparted to the impact table by the impact members can be shaped as desired by the user. Advantageously, the shock testing apparatus delivers an acceleration pulse and a deceleration pulse to the article being tested.

Ordinarily, in a test apparatus of this type, to compensate for tolerances in the construction and assembly of the component parts, the length of the swing arms and or mass of the impact members would be adjusted to help achieve synchronicity of impact. Similarly, the mass of the impact members and/or the drop height of the impact members may be altered to modify the shock pulse being imparted to the article being tested. In accordance with the present invention, the impactor plates 23 of the impact table 3 may be further provided with one or more coverings or pads 24 on their striking surface as shown in Figure 6.. The coverings or pads 24 may be formed from a resilient material, for example, but not limited to, rubberized material. Different coverings/pads 24 may comprise various material grades or thicknesses 24a, 24b. In this way, the shock pulse, and more specifically the rise- time, imparted to the impact table 2 may also or alternatively be shaped by altering the damping response through the provision and/or alteration of the coverings/pads 24 at selected impact plates 23. Thus with the present invention, the shock pulse imparted to the test object may be modified by any one or more of: varying the weight of the impact members 5; changing the drop height of the impact members 5; varying the thickness of the impact plates 23; providing pads having various hardnesses and/or thicknesses on selected impactor plates 23; changing the stiffness or preload of the damping members 6.

As shown in Figure 1 b, the shock testing apparatus 1 further comprises one or more data capture means located on said apparatus, such as but not limited to, high-speed cameras 12, strain gauges 13, accelerometers 14.

With reference to Figure 3, base structure 3 comprises side members 30, 31 and end members 32, 33. Side members 30, 31 are spaced apart and substantially parallel to each other, and the end members 32, 33 are spaced apart and substantially parallel to each other so that together they define a substantially rectangular frame. To increase the rigidity of base structure 3 one or more cross- members 36 (Figure 4) may be provided. Each corner of the base structure is provided with a casting 34 adapted to engage with a twistlock or other connector for secure mounting on a support surface, for example the ground or surface at a test location, or on the bed of a trailer or the deck of a vessel or platform. Such castings 34 are preferably ISO castings. In the Figures, base structure 3 is shown as rectangular frame however it will be appreciated that in alternative embodiments any suitable shape of base structure can be employed. Base structure is of rigid steel construction.

In one example, the base structure is nominally 6.058 m in overall length (L) and 2.44 m in overall width (W) as indicated on Figure 3. In this way, the base structure has substantially the same footprint as a standard 20 feet (ft) ISO container unit. The ISO footprint and provision of ISO casting adapted to receive standardised connectors enables the apparatus to be carried on a standard trailer and be secured in place at its place of use. As shown in Figure 8, the shock testing apparatus may further comprise removable side 37 and end 38 walls which are upstanding from the base structure 3 in use, and a top cover or coverings 39, which together conceal the apparatus within a container format and provide protection from the weather during transportation and storage. Thus the shock testing apparatus is convertible between a containerised, transport configuration and an assembled ordnance testing configuration. Optionally, the height of the walls 37, 38 when assembled extend to a nominal height of 2.6 mm above the ground engaging surface of the base structure 3.

The castings 34 provided on the base structure 3 also enable the apparatus to be positioned, for example by lifting by a crane, at a test or transport location. In addition, a plurality of apertures 35 (Figure 3) provided in base structure 3 adapted to receive the forks or tines of a forked lifting apparatus enable the apparatus to be readily moved.

To enable containerisation of the shock testing apparatus, various parts of the shock testing apparatus can be disassembled or moved into a stowed configuration. For example, as described above, the impactor raising means 56 may be pivoted from their operational positions as shown in Figure 1 b, to stowed positions as shown in Figure 10. In this way, the overall height of the shock testing apparatus may be reduced for transportation. Similarly, an impact member 5A and associated impact member support structure 4A otherwise located at one end of the apparatus and adapted to strike an end edge of the impact table 2 as shown in Figures 3 and 4, may be disassembled and located within the spaced defined by the footprint of the base structure 3 as shown in Figure 10.

Thus the shock testing apparatus 1 is portable and susceptible to transportation to explosive test ranges at any location. As the upper elements of the shock testing apparatus (e.g. impact member support structure 4, 4A, the impact members 5, 5A and swing arms 51 , raising and release mechanisms) are all demountable from the base structure 3 this enables the overall height of the apparatus to be reduced to allow for road transportation of the system in an ISO container format.

Optionally, the shock testing apparatus 1 forms part of an ordnance test system further comprising a storage container 60 (Figure 9) for storing and transporting any demountable elements of the shock testing apparatus and any ancillary equipment (for example, control cables, firing controller, spares etc.) of the shock testing apparatus, and for serving as a remote control and instrumentation collection centre 60 during shock testing operations. Optionally, the storage and remote control and instrumentation collection centre container 60 is a 20 feet (ft) ISO container. In this way, the shock testing apparatus 1 and the storage and remote control and instrumentation collection centre container 60 can be transported together, for example on the bed of a standard 40 feet (ft) trailer.

In another aspect of the invention there is provided a method of shock testing an item of ordnance, the method comprising the steps of: providing a shock testing apparatus 1 that is optionally convertible between a containerised transport configuration and an ordnance testing configuration; transporting the shock testing apparatus 1 to a test location; placing the shock testing apparatus onto a suitable surface; optionally converting the apparatus from its containerised transport configuration to its ordnance testing configuration; mounting an item of ordnance onto an impact table of said shock testing apparatus; and impacting the impact table with one or more impact members of said shock testing apparatus.

At a test site, the storage and remote control and instrumentation collection centre container 60 may be located at a suitable safe distance from the assembled shock testing apparatus 1 , with the necessary cabling for instrumentation and operation of the shock testing apparatus being extended between the assembled shock testing apparatus in its ordnance testing configuration and said collection centre container, before the test article 10 (Figure 1 b) is loaded onto the impact tables and is subjected to testing. The present invention thus provides a portable shock testing apparatus and method that allows a tunable shock impulse to be imparted to live ordnance in a safe, repeatable and cost-effective manner. Furthermore, the shock testing apparatus as described herein not only provides a valid means of testing ordnance but also provides a portable apparatus that can be relocated to any suitable test site but which, if subjected to a failed test, whereby the ordnance detonates with a subsequent high order explosion, would be of modest cost to replace. To this end, the apparatus has been designed to be of low cost, simple construction and of a configuration that the break-up of the machine is minimised to reduce fragment hazard.