Disclosure of Invention
In order to solve the problems, the invention discloses a wire laying method for increasing the laying stroke of a concave cylindrical surface, which effectively changes the stroke of a lifting shaft by applying pressure at an inclination angle and enlarges the processing range of equipment.
In order to achieve the purpose, the invention provides the following technical scheme:
a fiber laying method for increasing laying stroke of a concave cylindrical surface comprises the following steps:
step 1, designing a track according to a curved surface shape;
step 2, converting the track into a mechanical language, controlling the equipment to operate, and setting a pressing inclination angle of the thread laying head to be a positive value during operation;
step 3, laying the raw material on the surface of the curved surface through a wire laying head;
and 4, carrying out autoclave curing.
Further, the pressing inclination angle is controlled by the following formula:
wherein, Delta H is the safety margin of the lifting shaft of the equipment, and Delta H belongs to (0, Z)max-Zmin),ZmaxTo the upper limit of the stroke of the lifting shaft, ZminThe lower limit of the stroke is (x, y, z) the coordinates of the pressing point of the compression roller for spreading the silk, and L the length of the silk spreading head.
Further, Δ θ is calculated by:
when Z ismaxIf Δ H is larger than z + L · cos θ, Δ θ becomes smaller, and if f' (Δ H) is 0, Δ H and further Δ θ are obtained.
When Z ismaxIf Δ H is greater than z + L · cos θ, Δ θ is increased, and Δ H is made equal to 0 to obtain Δ θ.
Further, the pressing inclination angle is 8 °.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the invention adopts the inclination angle to press, lay and form the curved surfaces such as the semi-cylindrical concave curved surface, the cylindrical surface, the elliptic cylindrical surface, the vertical surface, the inclined plane and the like, controls the pressing direction of the pressing roller on the curved surface, and effectively reduces the stroke of the lifting shaft by adding the inclination angle of the fiber laying head, enlarges the working allowance of the lifting shaft, increases the processing range of the equipment, thereby realizing the fiber laying with larger curved surface stroke range in the limited stroke range of the lifting shaft. In a specific equipment processing range, the laying area can be enlarged to the maximum extent by adopting a mode of pressing by an inclination angle.
Detailed Description
The technical solutions provided by the present invention will be described in detail below with reference to specific examples, and it should be understood that the following specific embodiments are only illustrative of the present invention and are not intended to limit the scope of the present invention.
The invention provides a silk laying method for increasing laying stroke of a concave cylindrical surface, which carries out silk laying on a curved surface and comprises the following steps:
step 1, designing a track according to the shape of a curved surface
And 2, converting the track into a mechanical language and controlling the equipment to operate. In the step, the curved surface needing to be laid is laid and molded by applying pressure at an inclination angle. Wherein the curved surface includes but is not limited to the following: semi-cylindrical concave curved surface, cylindrical surface, elliptic cylindrical surface, vertical surface and inclined plane.
Fig. 1(a) is a schematic diagram of conventional laying in a cylindrical curved surface, wherein an arrow is a laying position, for simple calculation, the tail end of a lifting shaft is located at a circle center position, and the tail end is connected with a thread laying head. Theta is the included angle between the wire laying head and the negative direction of the z axis when the point is vertically pressed and laid, and is the supplementary angle of the included angle between the wire laying head and the lifting axis under the condition of vertical pressing. Fig. 1(b) shows a laying posture when the laying head provided by the present invention is inclined at a certain angle Δ θ when laying is performed at the same position, where Δ θ is a deviation angle based on a standard with a vertical downward pressing line as a base line.
In FIG. 1(b), the length of the line segment BC is dBCThe length of the line segment AB is dABThe height AC of the end of the machine tool lifting shaft is expressed as dAC。
dBC=R-Rcosθ (1)
dAB=dcos(θ+Δθ) (2)
dAC=R-Rcosθ+dcos(θ+Δθ) (3)
Where d is the total length of the laying head, R is the radius of the cylinder, and θ refers to the circumferential position on the cylinder of the current laying point. Theta is 0 vertically downward, positive to the right and negative to the left. The comparison shows that the height of the tail end of the lifting shaft can be reduced by R-dAC。
When the p point is laid, the shaft end is lifted and lowered at the coordinate origin by the method of vertical pressing as shown in fig. 1 (a). When the laying is carried out at point p by the method of applying pressure at an inclination angle shown in fig. 1(b), the position of the end of the lifting shaft is a. The same laying position can effectively reduce the stroke of the lifting shaft. Therefore, when the device is laid at the same laying height, the method of applying pressure by an inclination angle can effectively reduce the rising height (stroke) of the lifting shaft, expand the processing range and realize the maximum laying area in the range which can be reached by the device. This increases the amount of lift shaft clearance and ensures that the device does not exceed the travel range during operation of the device.
FIG. 2 is a graph showing the effect of the lift shaft stroke at angles of 0/3/-3/8/-8 degrees (we define that Δ θ rotates around point P on the ring counterclockwise to positive, clockwise to negative, and coincides with 0 in the radial direction), illustrating that the lift shaft stroke can be reduced at the same laying height while maintaining the pressure application inclination angle at a positive value. Fig. 2 is a graph focusing on analyzing the influence of positive and negative changes of an inclination angle on the equipment stroke, and the invention shows that when the pressing inclination angle delta theta is a positive value, the lifting shaft rises due to the change of the thread laying head, and the stroke of the lifting shaft is favorably reduced and the processing range is expanded when the thread laying head is laid at the same height, so that the allowance of the lifting shaft can be increased, and the equipment is ensured not to exceed the stroke range when the equipment runs.
Fig. 3-5 continue to explore the impact of tilt angle changes on equipment travel based on tilt angle being positive.
Further exploring the influence on the stroke of the lifting shaft when the pressing inclination angle is positive, as shown in fig. 3, when the pressing inclination angles are 0/2/4/6/8 degrees, respectively, a change curve of the influence on the stroke of the lifting shaft is obtained by laying the semicircular curved surfaces at different positions, which indicates that when the pressing inclination angle Δ θ is a positive value, the larger the inclination angle is, the smaller the stroke of the lifting shaft is at a certain laying height. In the same laying position, the larger the pressing inclination angle is, the larger the stroke amount of the lifting shaft is reduced. When the pressing inclination angle is 8 degrees, the height of the lifting shaft at the pressing point of 50 degrees is equivalent to the height of the pressing point at the bottommost part, and the effect of controlling the maximum stroke of the lifting shaft is obvious.
Based on the general condition of the fiber laying equipment, the influence condition of the inclination angle of 0-8 degrees on the lifting stroke is only analyzed in the embodiment, the method is not limited in the inclination angle range of 0-8 degrees, and the method can be expanded to a larger inclination angle range only by calculating boundary conditions through a formula as long as the equipment allows.
In the same laying position, the larger the pressing inclination angle is, the larger the stroke amount of the lifting shaft is reduced. When the pressing inclination angle is 8 degrees, the height of the lifting shaft at the pressing point of 50 degrees is equivalent to the height of the pressing point at the bottommost part, and the effect of controlling the maximum stroke of the lifting shaft is obvious.
FIG. 4 is a graph of increasing elevation of the lift shaft at different positions of the lay down. When the laying positions are 0, 10, 20, 30, 40 and 50 degrees in the circumferential direction of the cylinder, respectively, it can be found that the decrease of the stroke of the lifting shaft is larger when the inclination angle pressing is adopted as the laying position is increased. Taking the pressing inclination angle of 8 ° as an example, the relationship between the stroke of the lifting shaft and the position of the pressing point is shown in fig. 5, and the amount of reduction of the lifting shaft gradually decreases as the laying position increases. The reason for this is that when the pressing inclination angle is 8 °, the reduction of the lifting shaft is:
Δd=[R-Rcosθ+dcos(θ+8)]-[R-Rcosθ+dcos(θ+0)] (4)
Δd=-0.14dsinθ-0.01dcosθ (5)
since the sine value plays a dominant role, the amplitude of the height change of the lifting shaft is gradually reduced with the increase of the laying position.
Under the condition of a fixed pressing inclination angle, the stroke reduction amount of the lifting shaft is larger along with the gradual rise of the laying position relative to the position of the lowest point of the mold.
Obviously, the addition of the dip angle of the fiber spreading head can effectively reduce the stroke of the lifting shaft, enlarge the working allowance of the lifting shaft and increase the processing range of equipment. Therefore, the laying area can be enlarged to the maximum extent by adopting the inclination angle pressing mode within the processing range of a specific device. Under the condition that the arm length of the wire laying head is determined, the larger the inclination angle is, the larger the stroke allowance of the lifting shaft is. The inclination angle also depends on the situation of the equipment, and is limited mainly by the following two aspects: firstly, whether a mechanical structure of the equipment allows a larger inclination angle needs to ensure that a wire feeding mechanism does not interfere with the surface of a tool; and secondly, whether the rigidity of the device allows a larger inclination angle, the pressure applied by the laid wires sometimes reaches 1000N or more, the larger the inclination angle is, the larger the lateral torque in the track direction is, and larger loads are brought to a mechanical structure and a rotating shaft.
In order to improve the safety on the basis of applying pressure by adopting an inclination angle, the upper limit of delta theta is calculated according to the following method, and the safety allowance of an equipment lifting shaft is set to be delta H, and delta H epsilon (0, Z)max-Zmin) The upper limit of the stroke of the lifting shaft is ZmaxThe lower limit of the stroke is ZminAssuming that the coordinates of the pressing point of the pressing roller for spreading the yarns in fig. 1(b) are (x, y, z), wherein the y axis is perpendicular to the x and z axes, and the length of the yarn spreading head is L, the following formula is given:
L·cos(θ+Δθ)+z=Zmax-ΔH
the following can be obtained:
when Z ismaxIf Δ H is larger than z + L · cos θ, Δ θ becomes smaller, and if f' (Δ H) is 0, Δ H and further Δ θ are obtained.
When Z ismaxIf Δ H is greater than z + L · cos θ, Δ θ is increased, and Δ H is made equal to 0 to obtain Δ θ.
And 3, laying the prepreg tows (raw materials) on the surface of the curved surface.
And 4, carrying out autoclave curing.
According to the process, the addition or change of the inclination angle can effectively reduce the stroke of the lifting shaft, the processing range of the equipment is enlarged, and the processing range is larger when the inclination angle is larger. Conversely, the pressing inclination angle is reduced as much as possible to reduce the mechanical load of the apparatus and the load of the rotary shaft motor while ensuring the processing stroke.
The technical means disclosed in the invention scheme are not limited to the technical means disclosed in the above embodiments, but also include the technical scheme formed by any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and such improvements and modifications are also considered to be within the scope of the present invention.