JPS60158347A - Device for detecting interlayer separation of frp member - Google Patents

Abstract

PURPOSE:To detect the interlayer separation of an FRP member before the breakdown, by providing a long piece of carbon fiber, which has conductivity and low shear strength. CONSTITUTION:When a leaf spring S made of FRP repeatedly receives bending loads, shear stress acts between reinforced fibers 1 and 1. As a result, interlayer separation occurs, and the reinforced fibers 1 and 1 are relatively moved in the direction of orientation. A piece of long carbon fiber 2 is arranged in the side surface part of the leaf spring S so that the fiber 2 crosses the direction of orientation of the reinforced fiber 1 as a unitary body. The fiber 2 repeatedly receives the shearing force by the reinforced fibers 1 and 1, which are relatively moved in the oriented direction. Since the shear strength of the fiber 2 is low, it is broken by the shearing force in a short time. A DC power source 4 and a resistance meter 5 are connected to terminals 3 and 3, which are provided at the leaf spring S, and the resistance value is measured when periodic inspection and the like are conducted. When the fiber 2 is broken, it is found that the interlayer separation between the reinforced fibers 1 and 1 occurs. Thus, the breakdown of the leaf spring S can be positively detected beforehand.

Description

DETAILED DESCRIPTION OF THE INVENTION - (Industrial Application Field) The present invention relates to a delamination detection device that electrically detects delamination in an FRP member on which reinforced IIJi material is laminated.

(Prior art) In recent years, members that are subjected to repeated loads, such as leaf springs incorporated in automobile suspension systems, are molded with FRP to reduce the weight of automatic vehicles while ensuring their strength. ing.

However, this eel [RP] is made by laminating reinforcing fibers.
Since it is made of a four-layer body impregnated with resin, it has low interlayer strength and when used in a member that is subject to repeated bending loads, such as a leaf spring, as shown in Figure 6,
Shearing force acts repeatedly between the reinforcing fibers a and a, eventually causing delamination. In this case, since the delamination between the layers is not noticeable visually, it is left as is, and as a result, the F layer loses its rigidity between the layers.
There is a problem with RP members, which tend to break after a short period of use due to fatigue.

(Objective of the Invention) The object of the present invention is to detect delamination in JζF and RP members in advance, prior to rupture, in carbon fibers that have electrical conductivity and low strength. (Structure of the Invention) In order to achieve the above object, the solution of the present invention is a delamination detection device that electrically detects delamination in a living room of an FRP member on which reinforced tattrt is laminated. Carbon filaments to be inspected for the presence or absence of willow are arranged integrally and electrically independently inside or on the surface of the FRP member in a direction intersecting the orientation direction of the reinforcing fibers. .

In this regard, reinforcement of FRP members that have peeled off between layers ah
Relative movement in the orientation direction of the carbon filaments causes shear failure and disconnection, and the disconnection is detected by electrical testing, causing delamination of the FRP member.
11 It is designed to detect what has happened.

(Effects of the Invention) Therefore, according to the present invention, the carbon filaments disposed in the direction intersecting the orientation direction are shear-ruptured by the relative movement in the orientation direction of the reinforcing fibers of the delaminated FRP member. Delamination in FRP members can be detected by first breaking the wire and detecting the break through a current test.Unishitano can detect delamination in FR and P members in advance of the breakage. , F.R.
Unexpected breakage of the P member can be prevented.

(Example) Hereinafter, an example as a specific example of the technical means of the present invention will be described based on the drawings.

Figures 1 and 2 show a glass 5Iie reinforced FRP leaf spring S that is assembled into an automobile suspension.
A first embodiment in which the present invention is applied to is shown below. The leaf spring S is made of plate-shaped reinforcing fibers Irt1, 1. It is formed by impregnating a laminate with a resin and molding a laminate in which a large number of ... are stacked one above the other.

On the side surface of the leaf spring S, carbon long fibers 2, which are inspected for breakage by an electrical test, are disposed integrally with the leaf spring S and electrically independent. The carbon long fibers 2 are bonded in a meandering manner so as to intersect with the orientation direction (horizontal direction) of the reinforcing fibers 1 as shown in FIG. 2, and terminals 3.3 are provided at both ends thereof. and a resistor 315 are connected in series. Thus, the delamination detection device A is constituted by the carbon length 182 and the DC power source 4 and the resistance meter 5.

That is, when the leaf spring S is repeatedly subjected to bending loads, as shown in FIG. The fibers 1.1 move relative to each other in the orientation direction. At this time, the side surface of the leaf spring S is repeatedly subjected to shearing force by the reinforcing fibers 1.1 that move integrally and intersecting with the orientation direction of the reinforcing fibers 1, causing shear failure in a short time due to the low shear strength. The wire is disconnected.

Therefore, when performing vehicle inspections or periodic inspections of automobiles, the DC power supply 4 and resistance meter 5 are connected to each terminal 3, 3 provided on the leaf spring S to measure the resistance value, and the measured value is infinite. If so, it is known that the carbon long fibers 2 are broken and that one of the reinforced IJiMs 1 and 1 has peeled off between the eyebrows, and from this, the breakage of the leaf spring S can be accurately and reliably detected in advance. Therefore, it is possible to replace the leaf spring S with a new one without missing the replacement period. On the other hand, if the measured value is a finite value, it means that the carbon filament 2 is not broken and there is no delamination between any of the reinforcing fibers 1.1. It is possible to prevent the waste of replacing the spring S with a new one.

In the first embodiment, the carbon filaments 2 were bonded to the side surface of the leaf spring S, but the carbon filaments 2
The periphery of the leaf spring S is hardened with resin, molded into a sheet shape, and then pasted on the side surface of the leaf spring S to -tJ.

Further, FIGS. 4 and 5 show a second embodiment, and in the first embodiment, the carbon long fiber IR#2 was bonded to the side surface of the leaf spring S, but in this embodiment, the leaf spring S A communicating hole 6 that communicates with the top and bottom five surfaces of the leaf spring S is formed in the communicating hole 6, and a length made of carbon is formed in the communicating hole 6! l Navy 2
′ is inserted, and by solidifying the resin 7, the carbon fibers 2′ are formed integrally and electrically independently inside the spring S in a direction crossing the orientation direction of the reinforcing fibers 1. The delamination detection device A' is constructed by disposing the delamination detection device A', and provides the same effects as the first embodiment.

In the above-mentioned first and second embodiments, the DC power supply 4 and the resistance meter 5 are connected to the terminal 3°3 only when delamination is detected. It may be provided on a meter panel or the like, and an ammeter or voltmeter may be used instead of the resistor.

In addition, the leaf spring S is made of glass IIi reinforced FR.
Not only those made of P but also those molded from various other FRPs are acceptable. Furthermore, the present invention is of course applicable not only to leaf springs but also to eFRP members in which reinforcing fibers are laminated.

[Brief explanation of drawings]

Figures 1 to 3 show a first embodiment of the present invention, with Figure 1 being a perspective view, Figure 2 being a side view, and Figure 3 being an explanatory diagram of delamination.
Figures 4 and 5 show the second embodiment, and Figure 4 is partially oblique. Fig. f4 and Fig. 5 are main part sectional views, and Fig. 6 is an explanatory diagram of conventional delamination. S... Leaf sling 1 ring, 1... Reinforced m m, 2
, 2'...Carbon length 1#ffl, A, A'...
・Layer delamination detection device.

Claims (1)

[Claims] (1) Interlayer depression of FRP members laminated with strong synthetic fibers
This is a delamination detection device that electrically detects delamination, and the carbon filament, which is inspected for the presence or absence of disconnection by an electrical current test, is integrally and electrically independently installed inside or on the surface of the FRP member. A delamination detection device for an FRP member, characterized in that the device is disposed in a direction crossing the orientation direction of the reinforcing fibers.