Friction Material Elastic Characterization Device
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Solution Overview
Problem
Existing devices for characterizing the elastic properties of friction materials are limited by the influence of the measuring device structure, which overlaps with the material's response, especially at limited frequencies, leading to inaccurate measurements.
Innovation Solution
A device with a monoblock structure and a measuring column that includes a preloading screw, a piezoelectric actuator, load cells, and accelerometers, designed to minimize the influence of the device structure on measurements by applying controlled static and dynamic loads while maintaining axial symmetry to reduce deformation and vibration modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional measuring device structure is used for frequency characterization of elastic constants, then the measurement can be performed, but the structure of the measuring device overlaps with the material response especially at limited frequencies, leading to inaccurate measurements
Solution Approach 1:
The device is divided into a fixed support yoke and a movable measuring column that can be inserted into and removed from the yoke. This segmentation allows the measuring column to be independently designed with minimal structural influence on measurements, while the support yoke provides stable mounting. The separable design enables the measuring components to be isolated from the support structure, reducing overlapping vibrations between device and material.
Solution Approach 2:
A measuring column acts as an intermediary element between the support yoke and the specimen. The measuring column transmits forces and measurements while being designed to minimize its own structural interference with the specimen response. This intermediary structure allows force application and measurement without the support yoke directly contacting or influencing the specimen.
2Ease of manufacture
If the measuring device structure is simplified to reduce construction complexity, then the device becomes easier to construct, but the deformation and vibration modes of the structure may increase and interfere with measurements
Solution Approach 1:
The device separates the complex support functions (mounted in vehicle suspension) from the measurement functions (inserted into yoke). The support yoke with its mounting brackets and adjustment mechanisms provides ease of installation and positioning, while the simpler measuring column contains only the essential measurement components, reducing its deformation and vibration modes.
Solution Approach 2:
The measuring column is extracted as a separate, removable component from the support yoke. This extraction allows the measuring column to be designed with minimal necessary structure, reducing its own deformation characteristics that could interfere with measurements, while the support yoke handles all complex mounting and positioning functions.
3Measurement precision
If traditional measuring devices are used, then measurements can be conducted, but the excitation component influence cannot be adequately reduced
Solution Approach 1:
The measuring column is designed to be movable relative to the support yoke, allowing dynamic adjustment of the measurement setup. This dynamic capability enables optimal positioning and alignment that minimizes excitation component influence, while the modular design keeps overall device complexity manageable through standardized interfaces and assembly procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device provides reliable and accurate characterization of static and dynamic elastic properties of friction materials, reducing the impact of the measuring device structure and allowing for precise measurement of elastic constants, especially at higher frequencies relevant to braking systems.
Implementation Method 1
an actuator (12) capable of exerting, substantially along said device axis (X-X), an oscillatory thrust action having a predetermined period that is also variable in time in a controlled manner
Implementation Method 2
at least one load cell (13) suitable to detect the preloading action and the oscillatory thrust action exerted by said actuator
Implementation Method 3
at least one acceleration sensor or accelerometer (16) connected to said at least one support portion (14) to detect at least the acceleration of the support portion (14) generated by said oscillatory thrust action of the actuator (12) overlapping said preload
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A device (100) of characterization of the elastic properties of a friction material, comprising: - a support yoke (1) having a body (2) with a monoblock structure surrounding an inner chamber (3); - said inner chamber (3) being defined superiorly by a first monoblock body portion (2) or upper crossbar (4); - said inner chamber (3) being defined inferiorly by a second monoblock body portion (2) or lower crossbar (5); - said upper (4) and lower (5) crossbars being mutually connected by two side columns (6, 7) formed by a third and a fourth monoblock body portions (2); - said monoblock body comprising at least one access opening (8) to the inner chamber (3); - said upper crossbar comprising a threaded through hole (9) defining a device axis (X-X) arranged substantially orthogonal to said upper crossbar (4) and said lower crossbar (5) fully passing through the inner chamber (3); - said support yoke <(1) houses, substantially completely in said inner chamber (3), a measuring column (10); said measuring column (10) comprising transmission components of a static and dynamic actions, said components being arranged not necessarily in the order indicated herein below and being mutually arranged stacked substantially along said device axis (X-X) and suitable to be packed together between said upper (4) and lower (5) crossbars so as to transmit a static or dynamic action from one and the other: a preloading screw (11) suitable to engage in said threaded through hole (9) with at least one threaded length (22) thereof to enter said inner chamber (3) according to a predetermined displacement with respect to said upper crossbar (4) along substantially said device axis (X-X) to exert, once the measuring column (10) has been packed, a predetermined static preloading action; an actuator (12) capable of exerting, substantially along said device axis (X-X) an oscillatory thrust action having a predetermined period that is also variable in time in a controlled manner; - at least one load cell- (13) suitable to detect the preloading action and the oscillatory thrust action exerted by said actuator; at least one specimen support portion (14) to support a specimen of material to be tested (15) suitable to receive the preloading action by the preloading screw (11) and/or the oscillatory action of the actuator (12) and to transmit it to the specimen of material to be tested (15); at least one acceleration sensor or accelerometer (16) connected to said at least one support portion (14) to detect at least the acceleration of the support portion (14) generated by said oscillatory thrust action of the actuator (12); wherein - said measuring column (10) comprises a centering shaft (18). coupled to the end (17) of said preloading screw (11) projecting into said inner chamber (3); said centering shaft having a geometry substantially with a symmetry plane parallel to the device axis (X-X); said centering shaft (18) comprises at least one pair of geometric coupling portions (19) mutually arranged in opposite positions and for the direct or indirect geometric coupling to the monoblock body (2) of the support yoke (1), so as to be coupled to said centering screw to receive therefrom the axial preloading thrust but to avoid transmitting torsion actions to the remaining part of the measuring column (10), so as to transmit to said actuator (12) substantially a direct preloading action substantially along said device axis (X-X); - said measuring column (10) further comprises at least a ball joint (42) suitable to compensate for possible thrust misalignments between said preloading screw (11) and said actuator (12), and/or between said actuator (12) and said specimen support portion (14).