VEHICLE WITH A SYSTEM WITH ADJUSTABLE STIFFNESS FOR PEDESTRIAN PROTECTION

Abstract

Vehicle (10), comprising: a first vehicle component (26, 34, 40) containing a shape memory material (18); a heating element that can be selectively switched from an OFF state to an ON state to supply heat to the shape memory material (18); and at least one sensor (14) attached to the vehicle (10); characterized in that the shape memory material is a shape memory polymer (SMP) (18) having a first modulus of elasticity in a first state and a second modulus of elasticity in a second state, wherein the second modulus of elasticity is smaller than the first modulus of elasticity; wherein the SMP (18) transitions from the first state to the second state in response to the switching of the heating element from the OFF state to the ON state;and wherein the at least one sensor (14) is configured to generate an electrical signal in response to a force of a predetermined magnitude exerted on the vehicle (10) in order to switch the heating element from the OFF state to the ON state.

Description

INITIATIONThe information in this section is intended to generally illustrate the context of the disclosure. Work of the present inventors, insofar as described in this section, as well as aspects of the description that may not be prior art at the time of filing, are neither expressly nor silently admitted as prior art against the present disclosure.The present disclosure generally relates to a system having adjustable stiffness as needed of components under a hood or behind a bumper cover of a vehicle to meet legal and consumer safety requirements and, more particularly, to protect pedestrians upon impact with a moving vehicle. The disclosure is not limited in concept or approach to the following exemplary configurations, but may be extended to other applications in the automotive or non-automotive field where on-demand variation of the stiffness of a component is required in real time.Vehicle components are designed to meet cross-functional, often conflicting requirements. In some cases, these components must deform in a certain manner to meet the legal requirements and the safety requirements for consumers.For example, components may need to deform to meet the legal and safety requirements for consumers on pedestrian or occupant protection while at the same time maintaining their material and geometric stiffness to meet the requirements for durability, modal, and other cross-functional requirements. In other cases, internal components below an otherwise deformable component, such as a body outer panel, may maintain their stiffness and geometry upon contact with an object. For example, while the hood of a vehicle may deform during a head impact, the underlying vehicle parts are often non-deformable during such impact events.SUMMARYIn one configuration, a vehicle is provided that includes: a first vehicle component including a shape memory polymer (SMP) having a first modulus of elasticity in a first state and a second modulus of elasticity in a second state, the second modulus of elasticity being less than the first modulus of elasticity; a heating element selectively transitionable from an OFF state to an ON state to provide heat to the SMP, wherein in response to the transition of the heating element from the OFF state to the ON state, the SMP transitions from the first state to the second state; and at least one sensor mounted on the vehicle and configured to generate an electrical signal in response to a force of a predetermined magnitude applied to the vehicle, to transfer the heating element from the OFF state to the ON state.The vehicle may include one or more of the following optional features. The at least one sensor may be a piezoelectric sensor, for example. Additionally or alternatively, the at least one sensor may be disposed proximate a front panel of the vehicle.The first vehicle component may be located under a hood of the vehicle.In one configuration, the heating element may be a wire. The wire may be embedded in the SMP. Further, the wire may be in electrical communication with a power source of the vehicle, the wire receiving power from the power source when transitioning from the OFF state to the ON state.A switch may be in electrical communication with the at least one sensor. The switch may be switched from an open state to a closed state in response to the at least one sensor generating the electrical signal to power the heating element. Additionally or alternatively, the heating element may be a wire embedded in the SMP.In another configuration, a vehicle includes a first component having a first portion formed from a first material and a second portion formed from a shape memory polymer (SMP) having a first modulus of elasticity in a first state and a second modulus of elasticity in a second state, the second modulus of elasticity being less than the first modulus of elasticity, and a wire embedded in the second portion and selectively receiving current in a current carrying state to transition the SMP from the first state to the second state, and at least one sensor mounted to the vehicle and configured to generate an electrical signal to transition the wire to the current carrying state in response to a force of a predetermined magnitude applied to the vehicle.The vehicle may include one or more of the following optional features. The at least one sensor may be a piezoelectric sensor, for example. Additionally or alternatively, the at least one sensor may be disposed proximate a front panel of the vehicle.The first vehicle component may be located under a hood of the vehicle.In one configuration, the wire may be in electrical communication with a power source of the vehicle, the wire receiving power from the power source when energized. A switch may be in electrical communication with the at least one sensor. The switch may be switched from an open state to a closed state when the at least one sensor generates an electrical signal to provide current to the wire.In another configuration, a vehicle includes a first component having a first portion formed from a first material and a second portion formed from a shape memory polymer (SMP) having a first modulus of elasticity in a first state and a second modulus of elasticity in a second state, the second modulus of elasticity being less than the first modulus of elasticity, and at least one piezoelectric sensor mounted to the vehicle and configured to generate an electrical signal in response to a force of a predetermined magnitude applied to the vehicle to transition the SMP from the first state to the second state.The vehicle may include one or more of the following optional features. For example, a heating element may be selectively transitioned from an OFF state to an ON state to provide heat to the SMP, wherein the SMP transitions from the first state to the second state in response to the heating element being transitioned from the OFF state to the ON state. A switch may be in electrical communication with the at least one piezoelectric sensor, the switch configured to switch the heating element from the OFF state to the ON state in response to the generation of the electrical signal by the at least one piezoelectric sensor.BRIEF DESCRIPTION OF THE DRAWINGSThe drawings described herein are for illustrative purposes only of selected configurations and are not intended to limit the scope of the present disclosure. FIG. 1 is a perspective view of a vehicle according to the principles of the present disclosure; FIG. 2 is a partial exploded view of the vehicle of FIG. 1 showing a hood, a front trunk, a hood lid, and a visor with a shape memory polymer (SMP) at discrete locations; FIG. 3 is a partial exploded view of the vehicle of FIG. 1 showing a hood, a front trunk, a hood lid, and a visor in a softened state at one or more locations of the SMP; FIG. 4 is a functional block diagram showing a piezoelectric sensor in conjunction with a logic card that selectively enables current flow into the SMP in response to an electrical signal from the piezoelectric sensor; FIG. 5 is a partial side view of the vehicle of FIG. 1 in a first impact position relative to a crash test dummy; and FIG. 6 is a partial side view of the vehicle of FIG. 1 in a second impact position relative to a crash test dummy.Corresponding reference numerals designate corresponding parts in the drawings.DETAILED DESCRIPTIONExemplary configurations will now be described in more detail with reference to the accompanying drawings. Example configurations are provided so that this disclosure will be thorough and will fully convey the scope of the disclosure to those skilled in the art. Specific details are set forth, such as examples of specific components, devices, and methods, to provide a thorough understanding of configurations of the present disclosure. It will be understood by those skilled in the art that specific details need not be used, that example configurations may be implemented in many different forms, and that the specific details and the example configurations should not be construed to limit the scope of the disclosure.With particular reference to FIGS. 1 and 4, a vehicle 10 is provided that includes an adjustable on-demand stiffness (TSS) system 12 (FIG. 4 ) according to the principles of the present disclosure. As will be described in greater detail below, the TSS 12 responds to a pedestrian impact in real-time by making the vehicle structure softer at certain locations of the vehicle 10 so that the vehicle structure can controllably dissipate the forces associated with the contact of the vehicle 10 with the pedestrian or other vulnerable road user (VRU). In particular, the TSS 12 reduces head injury criteria (HIC) by allowing a first peak on a deceleration curve caused by the head of a pedestrian or VRU touching the vehicle 10 to be reached within three (3) milliseconds of the impact followed by a sudden drop. The TSS 12 achieves the above-described reduction in HIC by mitigating the vehicle structure in real-time in the area of impact with the head of a pedestrian or a VRU.The TSS 12 includes a series of sensors 14, a switch 16, and a shape memory polymer (SMP) 18 located at various locations of the vehicle 10. As will be described, the sensors 14 are configured to detect a pedestrian impact, which in turn causes the switch 16 to flow current into the SMP 18. The SMP 18 becomes softer by the applied current so that it can more easily deform when subjected to the forces associated with an impact.The sensors 14 may be piezoelectric sensors 14 that utilize the piezoelectric effect to measure changes in pressure, acceleration, temperature, strain, or force by converting the aforementioned changes to an electrical charge. In the present application, the piezoelectric sensors 14 generate electrical (stress) signals in response to a strain field. When the piezoelectric sensors 14 detect an impact event, the sensors 14 generate an electrical signal. In one configuration, upon detection of an impact, the piezoelectric sensors 14 generate an electrical signal in less than ten (10) milliseconds. The impact event may occur when the vehicle 10 contacts a pedestrian or other VRU, e.g., a cyclist. Alternatively, the impact event may also occur when the vehicle contacts another moving or stationary object. Regardless of which vehicle 10 is in contact with, piezoelectric sensors 14 are configured to sense the impact and generate an electrical signal in response to the event.The switch 16 is in communication with the piezoelectric sensors 14 and may be a logic card or printed circuit board (PCB) that causes current to flow into the SMP 18 via wires 19 embedded in the SMP 18 in response to the electrical signal or signals from the piezoelectric sensor or sensors 14. The current directed into the SMP 18 may be provided to the SMP 18 via the switch 16, which allows current to flow into the SMP 18 from an on-board power source, such as a vehicle battery 21. The current causes softening of the SMP 18.The SMP 18 may be mounted at various locations of the vehicle 10 where local softening of the vehicle structure is required to reduce the HIC values if the vehicle 10 impacts a pedestrian or other VRU. The SMP 18 may be mounted particularly where a pedestrian's head is likely to strike the vehicle 10 to more easily deform those areas of the vehicle 10 and absorb the energy associated with the applied load. The SMP 18 may be distributed among multiple locations as desired.In FIGS. 1 and 2, the piezoelectric sensors 14 are disposed at five (5) locations behind the front panel 20 of the vehicle 10. Although piezoelectric sensors 14 are described and shown as being disposed at five (5) locations behind front panel 20, more or fewer piezoelectric sensors 14 could be located behind front panel 20. Regardless of the number of piezoelectric sensors 14, the sensors 14 are arranged along a length of the front panel 20 at equal distances from each other and in a height direction (i.e., a Z direction) such that the sensors 14 are in close proximity to a leg of a pedestrian when standing in proximity to the front panel 20 of the vehicle 10. The sensors 14 may be positioned in the Z direction such that the sensors 14 are proximate the knee of a male crash test dummy of the 50thpercentile. Although the Z-direction position of the piezoelectric sensors 14 is described with respect to a male crash test dummy of the 50th percentile, the piezoelectric sensors 14 could be positioned at any height in the Z-direction that would expect a first impact of a pedestrian or other VRU due to the architecture and shape of the front end of the vehicle 10. Additionally or alternatively, although piezoelectric sensors 14 are described and illustrated below and in the drawings as being disposed in front fascia 20 of vehicle 10, sensors 14 may be mounted at any location of vehicle 10 where an occupant, pedestrian, or other VRU may impact the vehicle structure and thus benefit from mitigation of the vehicle structure. For example, a piezoelectric sensor 14 may be deployed within the passenger compartment 22 of the vehicle 10 at a location where an occupant may contact the vehicle structure. For example, a sensor could be placed near or within an instrument panel (IP) such that one or more sensors 14 are positioned to detect an impact event on the IP. In this configuration, the IP may include a support structure with SMP 18 to soften the IP and thus reduce the HIC during an impact.With continued reference to FIGS. 1 and 2, the SMP 18 is shown implemented in various vehicle structures under a hood 24 of the vehicle 10. In particular, the vehicle 10 of the present application may be an electric vehicle (EV) such that the vehicle 10 is propelled by one or more electric motors (not shown). Accordingly, there is no conventional internal combustion engine (ICE) that would normally be under the hood 24. Rather, a front trunk 26 (i.e., a combination of the terms "front" and "trunk") is located at a location where an ICE would be located to provide additional storage space for the vehicle 10. Although the TSS 12 is described and shown below in connection with an electric vehicle, the TSS 12 could also be used in connection with a vehicle structure connected to an internal combustion engine driven vehicle and / or to a hybrid electric vehicle (HEV) that includes both an internal combustion engine and one or more electric motors.As shown in FIG. 2, the front trunk 26 is generally disposed below the hood 24 and includes a series of walls 28 that cooperate with a floor panel 30 to form a storage compartment 32. The front trunk 26 may be closed by a hood lid 34 movably connected to the hood 24. The hood lid 34 includes a top panel 36 opposite the hood 24 and a series of walls 38 that cooperate with the top panel 36 to define a portion of the storage compartment 32 when the hood 24 is in a closed position and the hood lid 34 is in contact with the front trunk 26. Finally, a visor 40 may surround the front trunk 26 when the front trunk 26 is installed in the vehicle 10. Although the TSS 12 is described and shown in connection with a front trunk 26, a hood lid 34, and a visor 40, the TSS 12 may be used with any component under the hood 24, such as a headlamp (not shown).The front trunk 26, the hood lid 34, and the visor 40 may each include the SMP 18 in discrete locations. For example, the front trunk 26 may include the SMP 18 at discrete locations of the walls 28. Similarly, the hood lid 34 may include the SMP 18 at discrete locations of the walls 38, and the visor may include the SMP 18 at one or more side walls 42 and a rear wall 44. As shown in FIG. 2, the SMP 18 may have a substantially uniform height or alternatively may vary in height along the respective component 26, 34, 40. For example, the SMP 18 extending along and forming part of the walls 28 of the fuselage 26 may have a substantially uniform height. With respect to the SMP 18 extending along and forming part of the side walls 42 of the visor 40, the SMP 18 may have a variable height (i.e., an uneven height).The particular location and height of the SMP 18 in each of the aforementioned components 26, 34, 40 may be determined using computer-aided engineering (CAE) software to simulate the performance of the various components 26, 34, 40 in response to a load associated with a head impact. In CAE analysis, it is determined where the SMP 18 should be placed within a particular component (i.e., location, height, and / or uniform or non-uniform height) to optimize the component's ability to attenuate and reduce HIC. Accordingly, the location, height, and configuration of the SMP 18 for each component 26, 34, 40 may be tailored to the respective component 26, 34, 40 and the vehicle 10 in which the components 26, 34, 40 are installed. Moreover, the CAE analysis may take the surrounding components into account in the simulation to optimize performance of the entire vehicle structure at a particular location. In the present example, the CAE analysis may analyze and perform a simulation to determine the collective ability of the front trunk 26, the hood lid 34, and the visor 40 to reduce HIC by softening-at discrete locations of each component 26, 34, 40-in response to a head impact.In short, the CAE software and simulations will dictate the areas in the components that must be softer to meet the requirements of pedestrians and VRU in a head impact event. Localized areas of the components 26, 34, 40 may be replaced with the SMP 18 based on the CAE analysis to determine the exact position and amount of the SMP 18 to optimize performance of the respective component 26, 34, 40, as well as the system generally, in response to a load associated with a head impact.The SMP 18 may be integrally molded with the aforementioned components 26, 34, 40 using dual shot material. In particular, the SMP 18 may be molded with other polymers into the shapes shown for the trunk 26, the hood lid 34, and the visor 40. By forming the SMP 18 at locations dictated by the CAE analysis, the foregoing components 26, 34, 40 may be softened and tailored to reduce HIC when the vehicle 10 contacts a pedestrian or other VRU. In the casting of the components 26, 34, 40, the wire 19 may be embedded within the SMP 18 to allow the wire 19 to rapidly heat the SMP 18 from the inside during use.The SMP 18 connected to the aforementioned components 26, 34, 40 may be in electrical communication with an on-board power supply, such as the vehicle battery 21. Specifically, the SMP 18 may selectively receive current from the battery 21 when the switch 16 transitions from an open state to a closed state. As will be described in greater detail below, the switch 16 may transition from the open to the closed state in response to the piezoelectric sensors 14 generating an electrical signal. As shown in FIG. 4, the switch 16 is operatively disposed between the piezoelectric sensors 14 and the SMP 18. When one or more of the piezoelectric sensors 14 generate an electrical signal in response to an impact event, the electrical signal(s) causes / cause the switch 16 to transition from the open to the closed state to allow current to flow from the battery 21 to the SMP 18. The flow of current from the battery 21 to the SMP 18 causes the SMP 18 to soften, thereby allowing the components 26, 34, 40 to more easily deform in response to an impact or a downward force (i.e., in a direction substantially perpendicular to an outer surface 48 of the hood 24).The SMP 18 becomes softer due to its material properties by the applied current. The SMP 18 is, for example, a so-called smart polymer material that, when heated, transitions from a normal state having a first stiffness to a softened state having a second stiffness that is less than the first stiffness on a scale of 100x. In the present application, the current supplied from the battery 21 via the switch 16 causes a current flow within the SMP 18 via the wires 19 and thus heating the SMP 18. When the SMP 18 is heated, a phase change occurs such that the material properties (i.e., the modulus of elasticity (E)) of the SMP 18 change. In the present example, the modulus of elasticity of the SMP 18 is reduced, thereby reducing the ability of the SMP 18 to resist deformation when subjected to a load. Thus, when a load is applied to the hood 24 and the forces associated with the applied load are transmitted to the front trunk 26, the hood lid 34, and / or the visor 40, the locations of the SMP 18 in the aforementioned components 26, 34, 40 become softer, thereby reducing the ability of the components 26, 34, 40 to resist deformation. The position and amount of SMP 18 associated with each component 26, 34, 40, as well as the applied current, may be controlled in a desired manner for an optimal solution.When the switch 16 returns to the open state so that the components 26, 34, 40 are no longer powered by the battery 21 and the SMP 18 can cool, the SMP 18 returns to its elastic modulus (E). In this manner, the SMP 18 will recover its original stiffness. When the current no longer flows through the SMP 18 and the SMP 18 can cool, the SMP 18 returns to its original shape. Accordingly, in cases where the switch 16 transitions to the closed state and powers the SMP 18 but the vehicle 10 has not experienced an impact, the SMP 18 returns to its original stiffness (i.e., modulus of elasticity (E)) and shape when the switch 16 transitions to the open state and the SMP 18 may cool.With particular reference to FIGS. 1, 5, and 6, the operation of the TSS 12 will be described in detail. During operation of the vehicle 10, the piezoelectric sensors 14 continuously monitor the front panel 20 of the vehicle 10 for a change in applied load indicative of an impact event. Specifically, the piezoelectric sensors 14 constantly monitor the state in which the front panel 14 is subjected to a load of a certain magnitude. The load acting on the front panel 20 allows the sensors 14 to detect the impact event based on the load acting on one or more of the sensors 14 from the impact of the front panel 20 on a stationary or non-stationary object.The sensors 14 may be adjusted in a configuration such that the sensors 14 detect an impact event as soon as a threshold load is applied to them. In one configuration, the threshold load may be associated with the vehicle 10 contacting a particular crash test dummy at or above a predetermined speed. The threshold load may be associated with, for example, the vehicle 10 contacting a fifth percentile female crash test dummy 50 at a speed of five (5) miles per hour or more. The sensors 14 may be adjusted to generate an electrical (voltage) signal when a load equal to or greater than the predetermined load is applied to one or more of the sensors 14.When one or more of the sensors 14 sense a load equal to or greater than the predetermined load, the electrical signal generated by the one or more sensors 14 causes the switch 16 to transition from the open to the closed state. In this manner, as described above, the switch 16 allows current flow from the battery 21 into the SMP 18 of the front trunk 26, the hood lid 34, and the visor 40.As shown in FIGS. 5 and 6, the load change detected by the sensors 14 may be caused by a change in the strain field of one or more sensors 14. Specifically, this means that, when the vehicle 10 is first touched by a crash test dummy 50 (FIG. 5 ), one or more of the sensors 14 immediately detect a change in the expansion field of the respective sensor 14. The change in the strain field causes the sensor(s) 14 to generate an electrical signal that in turn switches the switch 16 from the open state to the closed state. When the switch 16 transitions from the open to the closed state, current may flow from the battery 21 into the SMP 18. It should be noted that the detection of the load change upon the first impact on the crash test dummy 50 takes place in less than ten (10) milliseconds. Accordingly, within ten (10) milliseconds, the sensor(s) 14 sense the crash event and cause / cause the switch 16 to transition from the open to the closed state. In the closed state, the switch 16 supplies the SMP 18 with current for a predetermined period of time, which depends on how much the elasticity (E) and the temperature must be changed.As the current flows into the front trunk 26, hood lid 34, and visor 40 at the SMP 18 of each component 26, 34, 40, the SMP 18 associated with the individual components 26, 34, 40 is heated and thereby softer. When the crash test dummy 50 moves to the position shown in FIG. 6 such that a head of the dummy 50 contacts the outer surface 48 of the hood 24, the SMP 18 is already heated and in a softened state. As the head of the dummy 50 deforms the hood 24, the underlying components 26, 34, 40 are softened and the energy generated upon contact of the head of the dummy with the hood 24 is absorbed more quickly and in a controlled manner. Accordingly, the dummy 50 experiences lower HIC.In the event that one or more of the sensors 14 detect a load change that exceeds the threshold but an impact event that requires softening of the components 26, 34, 40 over the SMP 18 is not required (i.e., when the vehicle 10 contacts a post or other stationary object and does not contact a pedestrian or other VRU), the switch 16 is still transitioned from the open state to the closed state to heat the SMP 18. However, the SMP 18 is not deformed when no force is applied to the hood 24 in a direction substantially perpendicular to the outer surface 48 of the hood 24. Thus, when the switch 16 returns to the open state and current is no longer applied to the SMP 18, the SMP 18 may cool and return to its original state. This scenario may be referred to as a false positive event because softening of the SMP 18 was not required to absorb the forces occurring upon contact between a pedestrian or other VRU and the hood 24 of the vehicle 10. If a false positive event occurs, the SMP 18 and, thus, the associated components 26, 34, 40 are automatically restored to their original state after cooling due to the nature of the SMP 18. Further maintenance or repair operations are not required to restore the SMP 18 or one of the associated components 26, 34, 40 to its original state.As described, the TSS 12 uses SMP 18 within vehicle components (i.e., components 26, 34, 40 in the example above) to provide the vehicle 10 with an as-needed response to the impact of a pedestrian or a VRU, while simultaneously allowing the components to meet the normal usage requirements during use of the vehicle 10. The TSS 12 powers the SMP 18 to warm the SMP 18 and thereby soften it upon impact of the vehicle 10 with a pedestrian or VRU. In this way, the TSS 12 lowers the HIC values to protect the pedestrian or the VRU. The components of the vehicle 10 provided with the SMP 18, the exact positions of the SMP 18, and the amount of the SMP 18 at the individual positions of the individual components may be determined using CAE analysis. Accordingly, the TSS 12 may be tailored to the particular vehicle 10.The terminology used herein is for describing particular exemplary configurations only and is not intended to be limiting. As used herein, the singular articles "a", "an", and "the / s" may also include the plural forms unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and therefore specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring execution in the order discussed or illustrated, unless expressly characterized as the order of execution. Additional or alternative steps may be employed.When an element or layer is referred to as being "on," "engaged," "connected," "attached to," or "coupled" to another element or layer, it may be directly on, engaged, connected, attached, or coupled to the other element or layer, or intervening elements or layers may be present. On the other hand, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," "directly attached to," or "directly coupled to" another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "next" versus "directly next," etc.). As used herein, the term "and / or" includes any combination of one or more of the associated listed items.The terms "first," "second," "third," etc., may be used herein to describe various elements, components, regions, layers, and / or portions. These elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or portion from another region, layer, or portion. Terms such as "first," "second," and other numerical terms do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer, or portion discussed below could be referred to as a second element, component, region, layer, or portion without departing from the teachings of the example configurations.In this application, including the definitions below, the term "module" may be replaced by the term "circuit". The term "module" may refer to, be part of, or include: an application specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor (shared, dedicated, or group) that executes code; memory (shared, dedicated, or group) that stores code executed by a processor; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, e.g., in a system-on-chip.The term "code" as used above may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, and / or objects. The term shared processor ("shared processor") includes a single processor that executes some or all of the code from multiple modules. The term "group processor" includes a processor that, in combination with other processors, executes some or all of the code from one or more modules. The term shared memory ("shared memory") includes a single memory that stores some or all of the code from multiple modules. The term "group memory" includes a memory that, in combination with other memories, stores some or all of the code from one or more modules. The term "memory" may be a subset of the term "computer readable medium.". The term "computer-readable medium" does not include transitory electrical and electromagnetic signals propagating through a medium and may therefore be considered tangible and non-transitory memory. Non-limiting examples of non-transitory memory include a tangible, computer-readable medium including a non-transitory memory, a magnetic memory, and an optical memory.The devices and methods described in this application may be partially or fully implemented by one or more computer programs executed by one or more processors. The computer programs include processor-executable instructions stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also contain and / or access stored data.A software application (i.e., a software resource) may refer to computer software that causes a computing device to perform a task. In some examples, a software application may be referred to as an "application," "app," or "program.". Exemplary applications include, but are not limited to, system diagnostic applications, system management applications, system maintenance applications, word processing applications, spreadsheet applications, messaging applications, media streaming applications, social network applications, and gaming applications.The non-transitory memory may be physical devices that are operable to temporarily or permanently store programs (e.g., command sequences) or data (e.g., program status information) for use by a computing device. The non-transitory memory may be a volatile and / or non-volatile addressable semiconductor memory. Examples of non-volatile memory include flash memory and read only memory (ROM) / programmable read only memory (PROM) / erasable programmable read only memory (EPROM) / electronically erasable programmable read only memory (EEPROM) (e.g., typically used for firmware such as boot programs). Examples of volatile memories include random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase change memory (PCM), and floppy disks or tapes.These computer programs (also referred to as programs, software, software applications, or code) contain machine instructions for a programmable processor and may be implemented in procedural and / or object oriented high-level language and / or in assembler / machine language. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, non-transitory computer-readable medium, apparatus, and / or device (e.g., magnetic disks, optical disks, memories, programmable logic devices (PLDs)) that is operable to provide machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal that serves to provide machine instructions and / or data to a programmable processor.Various implementations of the systems and techniques described herein may be implemented in digital electronic and / or optical circuits, integrated circuits, specially developed ASICs (application specific integrated circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations may include implementation in one or more computer programs executable and / or interpretable on a programmable system including at least one programmable processor that may be used for special or general purposes and is coupled to receive data and instructions from a storage system and to transmit data and instructions to a storage system, as well as at least one input device and at least one output device.The processes and logic flows described in this specification may be performed by one or more programmable processors, also referred to as data processing hardware, that execute one or more computer programs to perform functions by responding to input data and generating output. The processes and logic sequences can also be carried out by special logic circuits, for example an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit). Processors suitable for executing a computer program include, for example, both general and special purpose microprocessors and one or more processors of all types of digital computers. Generally, a processor receives instructions and data from a read-only memory or a random access memory, or both. The essential elements of a computer are a processor for executing instructions and one or more storage devices for storing instructions and data. Generally, a computer also includes or is operatively connected to one or more mass storage devices for storing data, e.g., magnetic, magneto-optical, or optical disks, for receiving or transmitting data therefrom. However, a computer does not need to have such devices. Computer readable media suitable for storing computer program instructions and data include any form of non-volatile memory, media, and storage devices including, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by special logic circuits or integrated into these.To enable interaction with a user, one or more aspects of the disclosure may be implemented on a computer having a display device, e.g., a CRT (cathode ray tube), LCD (liquid crystal display) monitor, or touch screen for displaying information to the user, and optionally a keyboard and a pointing device, e.g., a mouse or trackball, by which the user may make input to the computer. Other types of devices may also be used to interact with the user; the feedback to the user may be, for example, any form of sensory feedback, e.g., visual feedback, audible feedback, or tactile feedback; and inputs from the user may be received in any form, including audible, verbal, or tactile inputs. Moreover, a computer can interact with a user by sending and receiving documents to and from a device used by the user; e.g., by sending web pages to a web browser on a user's client device in response to requests received from the web browser.A number of implementations have been described. It should be understood, however, that various changes may be made without departing from the spirit and scope of the disclosure. Accordingly, other embodiments are also within the scope of the following claims.The foregoing description is for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular configuration are generally not limited to that particular configuration, but are optionally interchangeable and may be used in a selected configuration, although not specifically shown or described. It can also be varied in many ways. Such variations are not to be regarded as outside the disclosure, and all such changes are intended to be included within the scope of the disclosure.

Claims

A vehicle comprising: a first vehicle component including a shape memory polymer (SMP) having a first modulus of elasticity in a first state and a second modulus of elasticity in a second state, the second modulus of elasticity being less than the first modulus of elasticity; a heating element selectively transitionable from an OFF state to an ON state to provide heat to the SMP, wherein in response to the transition of the heating element from the OFF state to the ON state, the SMP transitions from the first state to the second state; and at least one sensor mounted on the vehicle and configured to generate an electrical signal in response to a force of a predetermined magnitude applied to the vehicle to transition the heating element from the OFF state to the ON state.The vehicle of claim 1, wherein the at least one sensor is a piezoelectric sensor.The vehicle of claim 1, wherein the at least one sensor is disposed proximate a front panel of the vehicle.The vehicle of claim 3, wherein the first vehicle component is located under a hood of the vehicle.The vehicle of claim 1, wherein the heating element is a wire.The vehicle of claim 5, wherein the wire is embedded in the SMP.The vehicle of claim 5, wherein the wire is in electrical communication with a power source of the vehicle, the wire receiving power from the power source when transitioning from the OFF state to the ON state.The vehicle of claim 1, further comprising a switch electrically connected to the at least one sensor.The vehicle of claim 8, wherein the switch is transitionable from an open state to a closed state in response to the at least one sensor generating the electrical signal to provide power to the heating element.The vehicle of claim 9, wherein the heating element is a wire embedded in the SMP.

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