WO2015034433A1

WO2015034433A1 - An apparatus and method for delaminating a layer-structured composite

Info

Publication number: WO2015034433A1
Application number: PCT/SG2014/000401
Authority: WO
Inventors: Yee Cheong Lam; Swee Hock YEO
Original assignee: Nanyang Technological University
Current assignee: Nanyang Technological University
Priority date: 2013-09-03
Filing date: 2014-08-26
Publication date: 2015-03-12
Anticipated expiration: 2016-03-03

Abstract

An apparatus (10) for delaminating a layer-structured composite (30), which includes at least first and second layers of different material properties bonded together, is disclosed. The apparatus comprises an actuator (6, 7, 8) configured to generate ultrasonic vibrations at a predetermined frequency; and a load generator (16) coupled to the actuator and configured to generate a predetermined force to act on the actuator, wherein in use, the actuator is arranged to contact the composite for applying the generated vibrations and force simultaneously to the composite to delaminate the first and second layers. A related method is also disclosed.

Description

AN APPARATUS AND METHOD FOR DELAMINATING A LAYER-STRUCTURED

COMPOSITE

Field

The present invention relates to an apparatus and method for delaminating a layer- structured composite.

Background

Two techniques are conventionally employed to separate a tri-layer-structured composite, for example, a tile-mortar-concrete composite, a glass-adhesive-ceramic composite, or a ceramic-adhesive-ceramic composite. The first conventional technique involves mechanically inserting a chisel (i.e. a hard tool with a sharp tip) into the soft (intermediate) layer of the composite, or along one of the interfaces of the composite. The terms 'soft layer' and 'hard layer' respectively refer to particular layers of the composite with low and high stiffness. This approach results in crack(s) initiation, and transverse bending force is then applied to propagate the crack(s) so as to completely dislodge the top and bottom layers. However, the said technique is not suitable for separating a composite with a large bonding area, or has top and bottom layers of high stiffness, where a large bending force is also required to induce crack propagation for separating the top and bottom layers.

*

The second conventional technique involves using an electrical jackhammer, i.e. a tool that combines an electrical motor, a hammer, and a chisel. The electrical motor is arranged to drive the hammer with up and down strokes, and at the down stroke, the hammer strikes the chisel to snag into the composite, normally from one side of the top layer of the composite. At the next up stroke, the chisel retracts from the composite and recovers to its original position. An operator of the jackhammer works to advance the snagging process over the entire surface of the composite. Two drawbacks are however notable with use of the jackhammer: (i) Loud noises are generated during the operation, and thus puts the operator and others in the vicinity of the work site at risk of hearing losses in the long term, and (ii) Substantial amount of strength is required to hold onto the jackhammer during operation to counteract violent back-pulsations generated by the jackhammer, particularly when working on a composite that has a top layer of extreme hardness. So over a long term, the back-pulsations of the jackhammer continuously transmitted to the operator's body may result in potential health and safety hazard. Yet another conventional solution uses an ultrasonic jackhammer, which drives the chisel with low-amplitude vibrations generated by a piezo-electric actuator. The ultrasonic jackhammer is operated at an ultrasonic frequency with the benefit that the operation is exceptionally quiet, because vibrating elements of the ultrasonic jackhammer are vibrating beyond the audible range (i.e. about greater than 20 kHz). However, it will be appreciated that during operation, the (electrical or ultrasonic) jackhammer causes structural damage to an object (being worked) due to the sharp tip of the chisel. Moreover, with poor control of chisel snags, there is also further possibility of causing structural damage down through to the intermediate and/or the bottom layers of the composite. Also, from a practical perspective, separating a layer- structured composite using the jackhammer is a slow and laborious process, due to the multiple snagging actions required for breaking the top layer into small debris. Hence, in using the jackhammer, a lengthy period of working time is often required for composites with a hard and large top layer.

One object of the present invention is therefore to address at least one of the problems of the prior art and/or to provide a choice that is useful in the art.

Summary

According to a first aspect of the invention, there is provided an apparatus for delaminating a layer-structured composite, which includes at least first and second layers of different material properties bonded together. The apparatus comprises an actuator configured to generate ultrasonic vibrations at a predetermined frequency; and a load generator coupled to the actuator and configured to generate a predetermined force to act on the actuator, wherein in use, the actuator is arranged to contact the composite for applying the generated vibrations and force simultaneously to the composite to delaminate the first and second layers.

The apparatus may further include a controller for controlling the actuator and the load generator.

The actuator may include a transducer arranged to generate the vibrations.

The actuator may further include a booster coupled to the transducer to receive the vibrations for adjusting the amplitude thereof. The actuator may further include a horn coupled to the booster to receive, amplify and apply the ultrasonic vibrations to the composite.

The horn may have a single blunt distal end, or a plurality of blunt distal ends.

The load generator may be pneumatically operated.

The apparatus may further include a moveable support device configured for supporting the actuator and the load generator.

The apparatus may also be configured as a hand-held unit.

The predetermined frequency may include an ultrasonic frequency. Specifically, the predetermined frequency_^may include a high frequency either internal or external of the ultrasonic frequency range.

According to a second aspect of the invention, there is provided a method for delaminating a layer-structured composite having at least first and second layers of different material properties bonded together. The method comprises a load generator generating a predetermined force to act on an actuator; the actuator generating ultrasonic vibrations at a predetermined frequency; and applying the generated vibrations and force simultaneously to the composite by contacting the actuator with the composite to delaminate the first and second layers. The method may further include applying a liquid medium to the actuator for contact with the composite.

Applying the generated vibrations and force may include applying the vibrations and force in a direction perpendicular to a top planar surface of the composite.

Alternatively, applying the generated vibrations and force may include applying the vibrations and force in a direction offset at an angle to a top planar surface of the composite. The predetermined frequency may include an ultrasonic frequency. Specifically, the predetermined frequency may include a high frequency either internal or external of the ultrasonic frequency range. It should be apparent that features relating to one aspect of the invention may also be applicable to the other aspects of the invention.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

Brief Description of the Drawings

Embodiments of the invention are disclosed hereinafter with reference to the accompanying drawings, in which:

FIG.1 is a schematic diagram of an ultrasonic apparatus for delaminating a layer- structured composite to separate top and bottom layers thereof, according to an embodiment of the invention;

FIG.2, which includes FIGs. 2a and 2b, shows respective photos of a homogeneous tile: (a), before and (b). after an operation cycle of the apparatus of FIG. 1 ;

FIG.3, which includes FIGs. 3a and 3b, shows respective photos of a glazed non- porcelain tile: (a), after three operation cycles of the apparatus of FIG. 1 applied at three different locations of the tile, and (b). after the fourth operation cycle of the apparatus of FIG. 1 ;

FIG. 4 is a schematic diagram of the apparatus of FIG. 1 used for damaging/breaking- up a soft layer of a bi-layered composite having a hard bottom layer; and Fig. 5 is a flowchart of an exemplary method of the invention.

Detailed Description

An exemplary embodiment of an ultrasonic apparatus 10 for delaminating a layer- structured composite is shown in FIG.1. "Layer-structured composite" refers to a composite (and hereafter referred to as such for brevity) with at least first and second layers of materials bonded together, in which each layer possesses different properties of stiffness and toughness. Examples of layer-structured composites include a bi- layered composite with a first (soft, i.e., low stiffness) layer arranged on top of a second (hard, i.e., high stiffness) layer, or a tri-layered composite with an intermediate first (soft) layer arranged between second and third (i.e., top and bottom hard) layers, or a tri-layered composite with a first (soft) layer adjacent second and third (hard) layers. In general, the apparatus 10 is configured to cause delamination of first and second layers of materials in a composite which may comprise further layers, the first layer typically being a soft layer and the second layer typically being a hard layer, "soft" and "hard" being relative between the first and second layers.

In the exemplary embodiment shown in FIG. 1 , the composite 30 is a tri-layered composite having an intermediate first (soft) layer 4 between a second (top) layer 5 and a third (bottom) layer 3 (which are both relatively hard). For example, the composite 30 may be a tile-mortar-concrete composite (wherein the first layer is the mortar, the second layer is the tile and the third layer is the concrete), a ceramic-adhesive-ceramic composite (wherein the first layer is the adhesive and the second and third layers are the ceramic), or the like. The apparatus 10 includes a sample holder 2 for releasably securing the composite 30 to a platform of the sample holder 2 to enable the composite 30 to be worked on by the apparatus 10. However, if the composite 30 is of a reasonably large size, the composite 30 may instead be placed directly on a levelled floor 1 , without using the sample holder 2 as will be appreciated. As depicted in FIG. 1 , the composite 30 is oriented within the sample holder 2 such that the top layer 5 is arranged above the soft layer 4 which is in turn above the bottom layer 3.

A controller 13, which includes an interface circuitry 14, is configured for controlling the apparatus 10, wherein the controller 13 may be any suitable controller, computer, or the like. Specifically, the controller 13 is coupled to an input device 12 (e.g. a keyboard or the like), and an output device 15 (e.g. a display or the like), via the interface circuitry 14, which also functions to electrically interface the controller 13 with other necessary controllable component parts of the apparatus 10. One such component part is a load generator 16 (e.g. a pneumatic cylinder or the like) which is part of the apparatus 10. The controller 13 is programmed via known programming techniques for controlling the apparatus 10 and the necessary controllable component parts as required.

The apparatus 10 further includes an ultrasonic power generator 11 , an ultrasonic transducer 8, a booster 7, and a horn 6 (which is configured with an output tip). The ultrasonic power generator 11 provides a desired electrical power for a predetermined time duration (as controllable), and converts standard electrical power (e.g. 240 volts, 50/60 Hz) into high frequency electrical energy required for operation of the apparatus 10. It is to be appreciated that the ultrasonic power generator 11 is interfaced with, and controllable via the controller 13.

The high frequency electrical energy produced by the power generator 11 is transmitted by a plurality of electrical conductors 9 (e.g. electrical cables) to the ultrasonic transducer 8. The ultrasonic transducer 8 then converts the received electrical energy into lateral ultrasonic vibrations. Herein, the term 'lateral ultrasonic vibrations' refers to high frequency (but low amplitude) oscillating mechanical motions moving along an axis parallel to the longitudinal axis of the ultrasonic transducer 8, and the direction of movement of the vibrations is indicated by a vertical two-headed arrow 18 in FIG. 1. Particularly, the said axis is the longitudinal axis of the apparatus 10: In other words, the ultrasonic vibrations are generated at a predetermined ultrasonic frequency.

The booster 7, being configurably disposed between the ultrasonic transducer 8 and the horn 6 as shown in FIG. 1 , mechanically converts and adjusts the ultrasonic vibrations generated by the ultrasonic transducer 8 into ultrasonic vibrations of different amplitude required to optimally delaminate the composite 30, based on requirements. The converted ultrasonic vibrations are transmitted to the horn 6, which is configurably coupled with the booster 7 in order to optimally receive and/or to further amplify the amplitude of the said ultrasonic vibrations. Collectively, the ultrasonic transducer 8, booster 7, and horn 6 may be termed hereafter as a transducer-booster-horn stack (or an actuator) for simplicity of description.

From FIG. 1 , it will be seen that the actuator is disposed in a vertical orientation using any suitable support means along the longitudinal axis of the apparatus 10, and above the composite 30 now being held in the sample holder 2. The actuator may also be arranged to be offset at a small incidental angle as measured from the longitudinal axis of the apparatus 10 to the interfaces of the composite 30. Offsetting the actuator at the small incidental angle is beneficial in terms of delivering not only vertical vibrations, but also horizontal vibrations by the horn 6 to the composite 30. In this way, the generated vibrations and force can be applied perpendicularly to the top planar surface of the composite or in a direction offset at an angle to the top planar surface of the composite. In particular, the aim of applying horizontal vibrations to the composite 30 is to promote sliding energy to contribute to greater effectiveness in delaminating the composite 30. In this instance, the actuator is integrated with the load generator 16 using a suitable support fixture 19, and in turn the load generator 16 is mounted to a frame structure 17 which rests on the floor 1. Roller wheels 20, each having a releasable lockable mechanism, are mounted at ends of respective legs of the frame structure 17 for conveniently moving the apparatus 10 from one location to another desired location. When the roller wheels 20 are unlocked, the frame structure 17 is movable, and when the roller wheels 20 are locked, the apparatus 10 is secured at a desired location.

The load generator 16 is controlled via the controller 13 and is arranged to move (via the support fixture 19) the actuator to an operation position (i.e. which is defined as a position where the output tip of horn 6 sufficiently contacts the top layer 5 of the composite 30). If required, a thin layer of a suitable medium 21 (e.g. a layer of liquid) which possesses good acoustic property may optionally be applied between the horn 6 and the top layer 5 of the composite 30 for effective transmission of the energy of the ultrasonic vibration to the composite 30. The load generator 6 is also configured to exert a predetermined amount of downward compressive force F onto a top planar surface of the composite 30 by controlled regulation of compressed air into the load generator 16. Alternatively, instead of the load generator 16, the compressive force F may also be generated via other suitable loading means. The compressive force F helps to facilitate effective transmission of the energy of the ultrasonic vibration onto the composite 30.

The "suitable loading means" may include arranging a weight (e.g. a deadweight) or simply the weight of a hand held unit (which the transducer-booster-horn stack may be configured as part of) to downwardly apply the compressive force F onto the top planar surface of the composite 30 . Alternatively, the same effect may also be achieved by applying a downward force exerted by an operator of the apparatus 10 onto the top planar surface of the composite 30 to remove the top layer 5 of the composite 30. In the above alternative instances, the loading is not applied at the transducer 8, but at the booster 7 (i.e., see FIG. 1 ), because the transducer 8 is a delicate electrical/mechanical component, and may be easily damaged by the heavy loading applied thereto, whereas the booster 7 is configured to have a suitable mounting to properly withstand and transfer (via the horn 6) the stress of the loading onto the composite 30.

While compressing the composite 30 with the compressive force F, the horn 6 applies the lateral ultrasonic vibrations to the top layer 5 to achieve delamination of the composite 30 between the first layer 4 and the second layer 4. The compressive force F and ultrasonic vibrations are controllably applied to the composite 30, as directed by the controller 13 and the power generator 11. An amount of the compressive force F and the ultrasonic vibration to be collectively applied onto the composite 30 is also influenced and determined by a particular design adopted for the horn 6. The output tip of the horn 6 may be of any suitable geometrical shape, and may be arranged with a single blunt distal end, or a plurality of blunt flat ends being in simultaneous contact with the top layer 5. The distal end(s) has a flat surface. Examples of possible shape configurations for the output tip of the horn 6, if a single flat end surface is desired, include circular, rectangular, and other possible polygon shapes. On the other hand, examples of possible shape configurations for the output tip of the horn 6, if multiple flat end surfaces are desired, include multiple shallow and small circular, rectangular, or other suitable polygon structures. Also, the small and shallow structures corresponding to the output tips of the horn 6 may be constructed in regular/irregular arrangement, and with same/different height, but each structure is to be arranged with a flat end surface.

An associated method for delaminating the composite 30 by using the proposed apparatus 10 is described below. Depending on a thickness of the composite 30, the composite 30 may or may not be mounted onto the sample holder 2, as afore explained. The composite 30 and the sample holder 2 (if used), are placed on the floor 1. The controller 13 is programmed to control the associated controllable component parts of the apparatus 10 to perform the following steps. First, the controller 13 actuates the load generator 16 to controllably move the transducer-booster-horn stack to the operation position, and to exert the compressive force on the composite 30. If necessary, a thin medium 21 is applied to substantially bridge a gap between the horn 6 and the top layer 5 of composite 30, before operation is started. The power generator 11 is then triggered so that the transducer 8 may start to provide the lateral ultrasonic vibrations, and the power generator 11 is specifically programmable (through the controller 13) to provide various ON/OFF duty cycles, as required for a particular application of ultrasonic vibration. The amplitude of ultrasonic vibrations transmitted to the horn 6 is controllable via the booster 7, and the vibrations are consequently applied to the composite 30 via the horn 6. It is to be appreciated that the vibrations are applied for a predetermined length of time (as necessary) for delamination of the composite 30 to occur.

Performance evaluations have been conducted using the apparatus 0 on the removal of a homogeneous tile which is the top layer of a tile-mortar-concrete composite. The said homogeneous tile has a surface area of approximately 150 by 150 mm², and is about 8 mm thick. In this instance, an ultrasonic horn with a circular flat end surface with a diameter of 28 mm was used as the horn 6. Effective separation of each homogeneous tile from underlying mortar-concrete layers (collectively of about 80 mm thick) was achieved under these evaluation conditions: (i) a compressive load F of about 180 N, (ii) an amplitude of the ultrasonic vibrations of 54 pm and (iii) associated time duration for applying the vibrations on the tile of 50 seconds.

FIGs. 2a and 2b are respective photos showing one such homogeneous tile: (a) before and (b) after an operation cycle as applied by the apparatus 10 on the homogeneous tile. Measured in accordance with Superficial Rockwell 15T Hardness Standard, the homogeneous tiles have an averaged HR value of about 91.02 ± 2.03. This hardness attribution of the homogeneous tiles results in effective ultrasonic vibration energy transmission across the thickness of the tile, and leads to dominant vibration energy attenuation and absorption of the ultrasonic vibrations in the soft mortar layer. It is noted that continuous application of high frequency vibrations will quickly exceed the modulus of toughness of the mortar layer, and consequently causes formation of crack(s) at an interface between the mortar layer and the top layer homogeneous tile. It is to be appreciated that none of the layers or the interface have any pre-existing score line prior to the operation. Further application of the ultrasonic vibrations (via the apparatus 10) then initiates and causes crack propagation along the interface between the mortar layer and the top layer, allowing separation of the homogeneous tile from the underlying concrete layer.

Compared to conventional jackhammers, the proposed apparatus 10 thus enables tile removal without need to significantly break up a tile (being worked) into small pieces of debris, and also causes no observable structural damage to the underlying concrete layer. In addition, compared to a generated noise level of about 95 dBA measured at a distance of 15 m from a sound source at which the conventional jackhammer is operated, according to measurements taken at 1 m from a sound source at which the apparatus 10 is operated, the proposed apparatus 10 generates only about 92 dBA (which is 2 orders of magnitude quieter). So, the apparatus 10 provides a more effective and substantially quieter operation for such tile removal. It is highlighted that for delaminating layer-structured composites with layers composed of different materials, process parameters for the apparatus 10 such as amplitude of the compressive force to be applied, an amount and amplitude of ultrasonic vibrations to be generated may conveniently and easily be adjusted (via the controller 13) to best suit requirements of a particular delamination operation.

Performance evaluations were also conducted using the apparatus 10 on the removal of a glazed non-porcelain tile which is the top layer for a tile-mortar-concrete composite. Each glazed non-porcelain tile has a surface area of approximately 150 by 150 mm², and is about 7 mm thick. Evaluation conditions adopted in this instance were similar to those used for evaluation of removal of the homogeneous tiles (as afore described). Each glazed non-porcelain tile was a two-layered composite, i.e., includes an approximately 0.35 mm thick hard glazed layer atop an approximately 6.65 mm thick bottom bisque layer. The respective average hardness for the hard glazed and bisque layers was determined to be 81.00 ± 2.41 and 54.98 ± 4.03, as measured in accordance with the Superficial Rockwell 15T Hardness Standard. With only a thin hard glazed layer and a thick soft bisque layer, the effective hardness of the glazed non-porcelain tile was thus less than the homogeneous tile. This means that compared to the homogeneous tile, the glazed non-porcelain tile better absorbs energy of the ultrasonic vibrations imparted (especially in the soft bisque layer) and may consequently be broken into small pieces. FIGs. 3a and 3b show respective photos of one such glazed non-porcelain tile: (a) after three operation cycles of the apparatus 10 as applied at three different locations of said glazed non-porcelain tile, and (b) after the fourth operation cycle of the apparatus 10. As a quick comparison, it is noted that for delaminating the homogeneous tile, a single ultrasonic vibration cycle of about 50 seconds duration was required, whereas for delaminating the glazed non-porcelain tile, multiple (e.g. generally around 5 to 7 times) short ultrasonic vibration cycles (each about 10 to 40 seconds long) are instead needed.

In addition to using the apparatus 10 for delaminating tiles from associated underlying mortar-concrete layers, the apparatus 10 is also advantageously usable to perform stress tests for selecting an optimally suitable bonding material with high fatigue resistance for a layer-structured composite (which includes reference to composites having at least two layers). As shown in FIG. 4, the proposed apparatus 10 may also be used to remove a soft layer 23 bonded underneath to a hard layer 22 of a bi-layered composite 40, but the energy of the ultrasonic vibration imparted by the apparatus 10 is instead concentrated at the interface of the composite 40, between the soft layer 23 and the hard layer 22. Examples of the bi-layered composite 40 include a composite with a thermoset adhesive bonded to a metal piece, a composite with a thermoset adhesive bonded to a hard ceramic, and so on. Specifically, continuous dissipation of the ultrasonic vibrations (by the apparatus 10 on the bi-layered composite 40) generates strain and heat energies in the bi-layered composite 40, particularly at the soft layer 23, to consequently cause cracks to form at the interface or within the soft layer 23, and consequently induces propagation of the cracks formed or break-up of the soft layer 23. Hence, this eventually leads to complete separation of the soft and hard layers 23, 22.

In summary, the proposed apparatus 10 is configured to apply the compressive force F and ultrasonic vibrations simultaneously via the horn 6 (e.g. configured with a flat end) to a layer-structured composite (being of at least two different layers). Working the apparatus 10 on the composite causes crack initiation and propagation at interface(s) between hard and soft layers of the composite, and/or within the soft layer of the composite. Thus, delamination of the composite is attained, and the apparatus 10 provides a means to easily and efficiently (in terms of energy usage) physically separate the different layers of the composite.

Specifically, at each vibration cycle, the hard layers (of the composite) enable effective transmission of vibrational energy across the thickness of said hard layers because the hard layers only vibrate within their linear elastic regime, absorbing little energy. Strain energy gained by the hard layers during each loading state (i.e. when the horn 6 moves into a position corresponding to a maximum amplitude of the vibration) is then released as mechanical energy during each unloading state (i.e. when the horn 6 moves into a position corresponding to a minimum amplitude of the vibration). It is to be appreciated that only a low level of vibration energy is absorbed as the strain energy is gained and released by the hard layers is approximately equal for each vibration cycle.

In contrast, the soft layer (of the composite) exhibits non-linear hysteresis stress-strain behaviour and absorbs significantly more energy at each vibration cycle than the hard layers. With the ultrasonic vibrations, it will be appreciated that there are about tens of thousands of cycles per second (e.g. about 20 * 10³ cycles/second). So within a short duration of time, the soft layer will likely absorb vibrational energy exceeding its associated toughness, leading to crack initiation and propagation along the interface between the soft and hard layers, and/or within the soft layer itself, which eventually results in delamination of the composite. Hence, using the apparatus 10 enables the damage, breakdown or removal of the soft layer directly to separate the hard and soft layers.

Advantageously, the proposed apparatus 10 thus enables the composite to be delaminated without requiring a large bending moment, and with little/no impact force imparted onto the composite. Further, using the horn 6 in the apparatus 10 to collectively apply the compressive force F and ultrasonic vibrations to the composite is beneficial as opposed to using a sharp tool (e.g. chisel) as per the conventional jackhammer, because unnecessary structural damage to underlying layers of the composite (not intended to be removed) may be minimized since the horn 6 is arranged with a blunt contact surface. Also, the proposed apparatus 10 provides a much quieter operation than conventional solutions.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary, and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practising the claimed invention. For example, the controller 13 and necessary holders and fixtures may all be integrated with the transducer-booster-horn stack to form a compact package, such as a hand-held unit. Also, alternatively, the apparatus 10 may be configured to generate the ultrasonic vibrations or at a high frequency close to ultrasonic range. Examples include a vibration frequency of 15 kHz that is external (i.e. a lower frequency vibration relative to the ultrasonic vibration) of the ultrasonic frequency range, or a vibration frequency of greater than/equal to 20 kHz (i.e. any frequency greater than/equal to 20 kHz, such as 35 kHz, is considered to be ultrasonic) that is within the ultrasonic frequency range.

Further, an alternative apparatus largely similar in configuration to the apparatus 10, but capable of generating acoustic vibration (i.e. vibration below the ultrasonic frequency) is also possible, e.g. at a frequency of 15 kHz. As a comparison, the apparatus 10 of FIG. 1 is arranged to generate ultrasonic vibrations at a frequency of 20 kHz, which is at the threshold of transition from acoustic frequency to ultrasonic frequency.

Claims

1. An apparatus for delaminating a layer-structured composite which includes at least first and second layers of different material properties bonded together, the apparatus comprising:

an actuator configured to generate ultrasonic vibrations at a predetermined frequency; and

a load generator coupled to the actuator and configured to generate a predetermined force to act on the actuator,

wherein in use, the actuator is arranged to contact the composite for applying the generated vibrations and force simultaneously to the composite to delaminate the first and second layers.

2. The apparatus of claim 1 , further including a controller for controlling the actuator and the load generator.

3. The apparatus of any preceding claims, wherein the actuator includes a transducer arranged to generate the vibrations.

4. The apparatus of claim 3, wherein the actuator further includes a booster coupled to the transducer to receive the vibrations for adjusting the amplitude thereof.

5. The apparatus of claim 4, wherein the actuator further includes a horn coupled to the booster to receive, amplify and apply the ultrasonic vibrations to the composite.

6. The apparatus of claim 5, wherein the horn has a single blunt distal end, or a plurality of blunt distal ends.

7. The apparatus of any preceding claims, wherein the load generator is configured to be pneumatically operated.

8. The apparatus of any preceding claims, further including a moveable support device configured for supporting the actuator and the load generator.

9. The apparatus of any preceding claims, wherein the apparatus is configured as a hand-held unit.

10. The apparatus of any preceding claims, wherein the predetermined frequency includes an ultrasonic frequency.

11. The apparatus of any of claims 1 to 9, wherein the predetermined frequency includes a high frequency either internal or external of the ultrasonic frequency range.

12. A method for delaminating a layer-structured composite having at least first and second layers of different material properties bonded together, the method comprising:

a load generator generating a predetermined force to act on an actuator; the actuator generating ultrasonic vibrations at a predetermined frequency; and

applying the generated vibrations and force simultaneously to the composite by contacting the actuator with the composite to delaminate the first and second layers.

13. The method of claim 12, further including applying a liquid medium to the actuator for contact with the composite.

14. The method of claim 12 or 13, wherein applying the generated vibrations and force includes applying the vibrations and force in a direction perpendicular to a top planar surface of the composite.

15. The method of claim 12 or 13, wherein applying the generated vibrations and force includes applying the vibrations and force in a direction offset at an angle to a top planar surface of the composite.

16. The method of any of claims 12 to 15, wherein the predetermined frequency includes an ultrasonic frequency. The method of any of claims 12 to 15, wherein the predetermined freque includes a high frequency external of the ultrasonic frequency range.