Bioinspired structural actuator

Abstract

The present invention relates to a method of manufacturing a bioinspired structural actuator (20) comprising at least a first material with a first thermomechanical propriety and a second material with a second thermomechanical propriety, the method comprising at least: - A first step of printing of one of the materials, - A second step of printing of the other material, the first step involving printing of a tubular structure (22) by mean of additive manufacturing process and in which the material includes or not continuous fiber reinforcement, the second step involving printing of a continuous winding composite structure (24) by mean of rotative printing process applied to continuous fiber reinforced composite on top of the tubular structure (22) made by the first step.

Description

[0001] DESCRIPTION

[0002] TITLE: BIOINSPIRED STRUCTURAL ACTUATOR

[0003] Technical field of the invention

[0004] The present invention relates to a bioinspired structural actuator and sensor that generate programmable motion.

[0005] Technical background

[0006] In the plant kingdom certain seed spreading and germination processes involve autonomous, complex morphing abilities with various morphological transitions. These processes integrate moisture sensing and actuation within a single biological structure, such as natural fiber cell walls. The latter have no muscle and rely on differential growth or expansion and material distribution to achieve complex autonomous and sequential shape changes.

[0007] Most of the current smart structures are made of stiff members connected and actuated by separate active devices based on energy intensive morphing principles, i.e., electromechanical devices for energy standby, sensing and motor drive functions. Also, most of the current smart structures consist in complicated assemblies that are prone to failure.

[0008] Thus, the aim of the invention is to propose a smart composite structure able to sense its environment and evidence a programmable / tailored motion actuation while being able to withstand mechanical loading without any external energy input.

[0009] The smart structure proposed by the invention is also easy to manufacture.

[0010] Summary of the invention

[0011] A first aspect concerns a method of manufacturing a bioinspired structural actuator comprising at least a first material with a first thermomechanical propriety and a second material with a second thermomechanical propriety, the method comprising at least:

[0012] A first step of printing of one of the materials,

[0013] A second step of printing of the other material, the first step involving printing of a tubular structure by mean of additive manufacturing process and in which the material includes or not continuous fiber reinforcement, the second step involving printing of a continuous winding composite structure by mean of rotative printing process applied to continuous fiber reinforced composite on top of the tubular structure made by the first step.

[0014] According to one or more embodiments:

[0015] - the first thermomechanical propriety and the second thermomechanical propriety of the materials are strictly different ;

[0016] - at least one of the materials include discontinuous fibers ;

[0017] - the first step includes the printing of at least one strand forming the tubular structure ;

[0018] - during the second step the continuous winding composite structure is printing around the at least one strand made from the first step ;

[0019] - at least one material is composed of continuous fibers reinforced polymer and / or carbon and / or natural fiber and / or ceramic fiber and / or glass fiber ;

[0020] - at least one material is composed of discontinuous fibers reinforced polymer and / or carbon and / or natural fiber and / or ceramic fiber and / or basalt fiber and / or glass fiber and / or metallic fiber ;

[0021] - at least one material is composed of particles reinforced polymer carbonous base.

[0022] A second aspect concerns a bioinspired structural actuator obtained by the method one of the above features, comprising at least a first material with a first thermomechanical propriety and a second material with a second thermomechanical propriety and comprising at least a tubular structure made into one of the materials and comprising a continuous winding composite structure extending around the tubular structure and made into the other material.

[0023] According to one or more embodiments: - the tubular structure is able to move from a neutral position to an active position in which the tubular structure moves along and / or around at least one axis of revolution under the effect of at least one environmental stimulus ;

[0024] - the continuous winding composite structure is used to guide and control the movements of the tubular structure along and / or around at least one axis of revolution under the effect of at least one environmental stimulus ;

[0025] - the at least one environmental stimulus is temperature and / or temperature variation ;

[0026] - the tubular structure comprises at least one helical strand, the continuous winding composite structure extending on top of the strand.

[0027] Brief description of the figures

[0028] [Fig .1 ] shows a bioinspired structural actuator according to a first example of the invention comprising a tubular structure and a continuous winding composite structure on top of the tubular structure, in which the tubular structure is in a neutral position ;

[0029] [Fig.2] shows the bioinspired structural actuator of figure 1 in which the tubular structure is in an active position ;

[0030] [Fig.3] shows a bioinspired structural actuator according to a second example of the invention comprising two strands forming the tubular structure and a continuous winding structure extending on top of each strand ;

[0031] [Fig.4] shows a diagram of the steps involved in a method of manufacturing the bioinspired structural actuator.

[0032] Detailed description of embodiments

[0033] In the following description, identical, similar, or analogous elements will be designated by the same reference numbers.

[0034] Figure 1 shows a bioinspired structural actuator 20 comprising at least a tubular structure 22 and a continuous winding composite structure 24 formed around the tubular structure 22. The bioinspired structural actuator 20 comprises a first material with a first thermomechanical propriety and a second material with a second thermomechanical propriety, the first thermomechanical propriety and the second thermomechanical propriety being strictly different.

[0035] A thermomechanical property is defined as a property namely expansion and elastic properties conditioned by temperature and / or temperature variation coming directly from the environment or induced by a user directly on the materials and which involves at least one modification to the structure of the material.

[0036] According to an example of the invention, at least one of the first and second materials may be composed of continuous fibers reinforced polymer and / or carbon and / or natural fiber and / or ceramic fiber and / or glass fiber.

[0037] According to an alternative or additional example of the invention, at least one of the first and second materials may be composed of discontinuous fibers reinforced polymer and / or carbon and / or natural fiber and / or ceramic fiber and / or basalt fiber and / or glass fiber and / or metallic fiber.

[0038] According to an alternative or additional example of the invention, at least one of the materials is composed of particle reinforced polymer carbon base.

[0039] According to the invention, the tubular structure 22 can be composed of the first material, or the second material and the continuous winding composite structure 24 can be composed of the other material.

[0040] It is understood that the material composing the tubular structure 22, and the material composing the continuous winding composite structure 24 are chosen in accordance with their thermomechanical properties.

[0041] According to the invention, the tubular structure 22 forms an active portion of the bioinspired structural actuator 20 and the continuous winding composite structure 24 can form a passive portion or an active portion of the bioinspired structural actuator 20.

[0042] In other words, the tubular structure 22 is configured to move from a neutral position shown in figure 1 to an active position shown in figure 2, during which the tubular structure 22 moves along and / or around at least an axis of revolution A of the tubular structure 22, under the effect of at least one environmental stimulus.

[0043] The continuous winding composite structure 24 is used to guide and control the movements of the tubular structure 22 according to its thermomechanical propriety. Alternatively, when the continuous winding composite structure 24 is also an active portion of the bioinspired structural actuator 20, it is able of reacting to at least one environmental stimulus in such a way that it controls the movements of the tubular structure 22 according to its thermomechanical propriety.

[0044] It must be considered that the thermomechanical propriety of the continuous winding composite structure 24 can be adjust also depending on the structure and / or pattern of the continuous winding composite structure 24 on top of the tubular structure 22.

[0045] Also, the tubular structure 22 is able to return to its neutral position when thermal stimulation is over.

[0046] In the context of the invention, it is understanding that the environmental stimulus is a temperature variation.

[0047] It is also understood that the material composing each of the tubular structure 22, and the continuous winding composite structure 24 are chosen such that it allows the tubular structure 22 to be an active portion of the bioinspired structural actuator 20 and such that it allows the continuous winding composite structure 24 to be a passive or an active portion of the bioinspired structural actuator 20.

[0048] Thus, the tubular structure 22 is configured to move from its neutral position to its active position under the effect of a temperature variation of the environment. The first material or the second material composing the tubular structure 22 has therefore a thermomechanical propriety allowing the tubular structure 22 to react to a determined temperature variation.

[0049] For example, the first material or the second material use in the tubular structure 22 could be chosen to react within a specific temperature range depending on the environment in which the bioinspired structural actuator 20 is used.

[0050] Furthermore, when the continuous winding composite structure 24 is configured to be an active part of the bioinspired structural actuator 20, the material used in the continuous winding composite structure 24 is chosen such that it reacts to a specific temperature range depending on the environment in which the bioinspired structural actuator 20 is used and depending on the desired behaviour of the continuous winding composite structure 24.

[0051] As illustrated in figure 1 , the continuous winding composite structure 24 comprises a plurality of filaments 25 extending around the tubular structure 22 such that they form a helical pattern.

[0052] The filaments 25 of the continuous winding composite structure 24 of the bioinspired structural actuator 20 are spaced apart by a set distance which may be adjusted depending on the desired behaviour of the continuous winding composite structure 24 on the tubular structure 22.

[0053] Also, the filaments 25 of the continuous winding composite structure

[0054] 24 of the bioinspired structural actuator 20 extends around the tubular structure 22 with a set tilt angle from 0° to 90° by considering a plane perpendicular to the axis of revolution A of the tubular structure 22 of the bioinspired structural actuator 20. It must be considered that the tilt angle can be constant or variable around the tubular structure 22.

[0055] It is understood that the tilt angle may be adjusted in function of the desired behaviour of the continuous winding composite structure 24 on the tubular structure 22.

[0056] As well, the number of filaments 25 of the continuous winding composite structure 24 around the tubular structure 20 may be adjusted in function of the desired behaviour of the continuous winding composite structure 24 on the tubular structure 22.

[0057] According to another example illustrate at figure 3, the tubular structure 22 can comprise at least one strand 26.

[0058] According to figure 3, the tubular structure 22 comprises two strands 26.

[0059] Each strand of the tubular structure 22 comprises at least one filament

[0060] 25 of the continuous winding composite structure 24 extending around it.

[0061] According to the example illustrated, each of the two strands 26 of the tubular structure 22 comprises four filaments 25 of the continuous winding composite structure 24 extending in a helical shape such that they follow the shape of the strands 26.

[0062] It is understood from the description above that the bioinspired structural actuator 20 is configured such that it can have a rotative move around the axis of revolution A of the tubular structure 22, from the neutral position to the active position, here only under the effect of temperature or temperature variation.

[0063] In other words, the bioinspired structural actuator 20 can generate a rotational response without the need for external energy from human sources.

[0064] Also, the rotational response can be controlled and adjusted according to the composition of each of the first and second material s and according to the structure and layout of the continuous winding composite structure 24.

[0065] The bioinspired structural actuator 20 may be use for example but not limited to, as a smart platform or mast for passive rotation actuation of a passive solar tracker subjected to photothermal effect from sun rays.

[0066] Other examples include but are not limited to, the bioinspired structural actuator 20 used as a thermal actuator within a valve, a rotary jack or used within a deployable device.

[0067] A method 10 of manufacturing of the bioinspired structural actuator 20 will now be describe according to figures 1 to 4.

[0068] The method 10 of manufacturing comprises at least a first step 100 of printing of one of the first or second materials, and a second step 200 of printing of the other material.

[0069] More precisely, the first step 100 involves printing of the tubular structure 22 of the bioinspired structural actuator 20 and the second step 200 involves printing of the continuous fiber reinforced composite winding composite structure 24.

[0070] It is thus understood that the used of the first material or the second material in each of the first and second step 100, 200 depends on the desired rotational response of the bioinspired structural actuator 20.

[0071] According to the invention, the first step 100 is implemented by mean of additive manufacturing process. According to the invention, the second step 200 is implemented by a rotative printing process applied to continuous fiber reinforced composite on top of the tubular structure 22.

[0072] More precisely, the second step 200 involve a continuous deposition of the filaments 25 composed of one of the materials on top of the tubular structure 22.

[0073] In other words, the second step 200 generates a set of filaments forming a monobloc unit named continuous winding composite structure 24.

[0074] It must be considered that during the first and second steps 100, 200, both materials can include continuous fiber reinforcement, or only the continuous winding composite structure 24 include continuous fiber reinforcement.

[0075] Alternatively, or additionally, at least one of the materials can include discontinuous fiber.

[0076] According to an example of the invention, the first step 100 may include the printing of at least one strands 26 forming the tubular structure 22. Thus, the second step 200 includes the printing of at least one filament 25 of the continuous winding composite structure 24 on top of the at least one strand 26.

Claims

CLAIMS1 . Method (10) of manufacturing a bioinspired structural actuator (20) comprising at least a first material with a first thermomechanical propriety and a second material with a second thermomechanical propriety, the method (10) comprising at least:- A first step (100) of printing of one of the materials,- A second step (200) of printing of the other material, the first step (100) involving printing of a tubular structure (22) by mean of additive manufacturing process and in which the material includes or not continuous fiber reinforcement, the second step (200) involving printing of a continuous winding composite structure (24) by mean of rotative printing process applied to continuous fiber reinforced composite on top of the tubular structure (22) made by the first step (100).

2. Method (10) according to the preceding claim, in which the first thermomechanical propriety and the second thermomechanical propriety of the materials are strictly different.

3. Method (10) according to any one of the preceding claims, in which at least one of the materials include discontinuous fibers.

4. Method according to any one of the preceding claims, in which the first step includes the printing of at least one strand (26) forming the tubular structure (22).

5. Method (10) according to the preceding claim, in which during the second step (200) the continuous winding composite structure (24) is printing around the at least one strand (26) made from the first step (100).

6. Method (10) according to any one of the preceding claims, in which at least one material is composed of continuous fibers reinforcedpolymer and / or carbon and / or natural fiber and / or ceramic fiber and / or glass fiber.

7. Method (10) according to claim 3, in which at least one material is composed of discontinuous fibers reinforced polymer and / or carbon and / or natural fiber and / or ceramic fiber and / or basalt fiber and / or glass fiber and / or metallic fiber.

8. Method (10) according to claim 6, in which at least one material is composed of particles reinforced polymer carbonous base.

9. Bioinspired structural actuator (20) obtained by the method (10) of any of claims 1 to 8, comprising at least a first material with a first thermomechanical propriety and a second material with a second thermomechanical propriety and comprising at least a tubular structure (22) made into one of the materials and comprising a continuous winding composite structure (24) extending around the tubular structure (22) and made into the other material.

10. Bioinspired structural actuator (20) according to claim 9, in which the tubular structure (22) is able to move from a neutral position to an active position in which the tubular structure (22) moves along and / or around at least one axis of revolution (A) under the effect of at least one environmental stimulus.11 . Bioinspired structural actuator (20) according to claim 10, in which the continuous winding composite structure (24) is used to guide and control the movements of the tubular structure (22) along and / or around at least one axis of revolution (A) under the effect of at least one environmental stimulus.

12. Bioinspired structural actuator (20) according to any of claims 10 or11 , in which the at least one environmental stimulus is temperature and / or temperature variation.

13. Bioinspired structural actuator (20) according to any of claims 9 to12, in which the tubular structure (22) comprises at least one helical strand (26), the continuous winding composite structure (24) extending on top of the strand (26).

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