JP3305145B2 - Fatigue damage measurement method - Google Patents
Fatigue damage measurement methodInfo
- Publication number
- JP3305145B2 JP3305145B2 JP00882195A JP882195A JP3305145B2 JP 3305145 B2 JP3305145 B2 JP 3305145B2 JP 00882195 A JP00882195 A JP 00882195A JP 882195 A JP882195 A JP 882195A JP 3305145 B2 JP3305145 B2 JP 3305145B2
- Authority
- JP
- Japan
- Prior art keywords
- fatigue damage
- degree
- square roughness
- structural member
- roughness
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、低サイクル疲労負荷を
受ける機械構造物等に適用される疲労損傷度測定方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the degree of fatigue damage applied to a mechanical structure or the like subjected to a low cycle fatigue load.
【０００２】[0002]
【従来の技術】従来の繰返疲労負荷を受ける機械構造物
等の疲労損傷度（使用繰返数Ｎ×１００／破断繰返数Ｎ
ｆ）については、構造物等に加えられる温度，圧力，応
力等を計測することにより測定されるものはあったが、
表面形状を計測することにより疲労損傷度を測定し、余
寿命を評価するものは見当らない。2. Description of the Related Art The degree of fatigue damage of a mechanical structure or the like subjected to a conventional repeated fatigue load (the number of used cycles N × 100 / the number of repeated cycles N)
As for f), there are some which are measured by measuring the temperature, pressure, stress, etc. applied to a structure or the like,
There is no one that measures the degree of fatigue damage by measuring the surface shape and evaluates the remaining life.
【０００３】[0003]
【発明が解決しようとする課題】従来の構造物等の疲労
損傷度の計測については、前記のように構造物等に加え
られる温度，圧力，応力等を計測することにより行われ
ていた。Conventionally, the degree of fatigue damage of a structure or the like has been measured by measuring the temperature, pressure, stress, etc. applied to the structure or the like as described above.
【０００４】しかしながら、いずれの計測方法を用いた
場合にも、その計測結果より構造物等の余寿命を的確に
予測することはむずかしく、特に、寿命の初期段階でこ
れを予測することは不可能に近かった。本発明は上記の
課題を解決しようとするものである。However, it is difficult to accurately predict the remaining life of a structure or the like based on the measurement result in any case of using any of the measurement methods. In particular, it is impossible to predict the remaining life at an early stage of the life. It was close to The present invention seeks to solve the above problems.
【０００５】[0005]
（１）本発明の疲労損傷度測定方法は、予め繰返疲労負
荷を受ける構造部材の試験片について表面の二乗平均粗
さと疲労損傷度の関係を求めておき、使用中の構造部材
について計測対象部位表面を鏡面に仕上げた後、最大負
荷荷重方向に直線状に表面の形状を計測し、この計測結
果から二乗平均粗さを計算し、更に、この二乗平均粗さ
について初期状態からの変化量を求めた後、上記予め求
めた二乗平均粗さと疲労損傷度の関係から上記構造部材
の疲労損傷度を求めることを特徴としている。(1) The method for measuring the degree of fatigue damage according to the present invention obtains the relationship between the root-mean-square roughness of the surface and the degree of fatigue damage on a test piece of a structural member subjected to repeated fatigue load in advance, and measures the structural member in use. After finishing the surface of the part to a mirror surface, measure the surface shape linearly in the direction of the maximum load, calculate the root-mean-square roughness from the measurement results, and further calculate the amount of change in the root-mean-square roughness from the initial state. , The degree of fatigue damage of the structural member is determined from the relationship between the previously determined root mean square roughness and the degree of fatigue damage.
【０００６】（２）本発明は、上記発明（１）に記載の
疲労損傷度測定方法において、二乗平均粗さに代えて中
心線平均粗さを用いることを特徴としている。(2) The present invention is characterized in that, in the method for measuring the degree of fatigue damage according to the invention (1), the center line average roughness is used instead of the root mean square roughness.
【０００７】（３）本発明は、上記発明（１）に記載の
疲労損傷度測定方法において、二乗平均粗さに代えて十
点平均粗さを用いることを特徴としている。(3) The present invention is characterized in that, in the method for measuring the degree of fatigue damage according to the invention (1), a ten-point average roughness is used instead of the root mean square roughness.
【０００８】[0008]
【作用】初期に滑らかな表面をもっていた構造部材が繰
返疲労負荷を受けると、まず、表面に塑性変形によるす
べり帯があらわれ、次に、突き出し、入り込み等の凹凸
があらわれ、ミクロき裂の発生・成長、マクロき裂の発
生・成長を経て破断へとつながる。[Function] When a structural member having a smooth surface in the beginning is subjected to repeated fatigue load, first, a slip band due to plastic deformation appears on the surface, and then irregularities such as protrusion and intrusion appear, and micro cracks are generated.・ Growth, generation of macro-cracks, leading to fracture through growth.
【０００９】上記発明（１）は、この点に着目して種々
実験を重ねた結果、使用中の構造部材の表面の二乗平均
粗さと疲労損傷度との間には、相関関係があることを見
出したことによるものである。In the above invention (1), as a result of repeated experiments focusing on this point, it was found that there is a correlation between the root mean square roughness of the surface of the structural member in use and the degree of fatigue damage. This is due to the finding.
【００１０】そのため、予め試験片について表面の二乗
平均粗さと疲労損傷度の関係を求めておき、使用中の構
造部材について表面の形状を計測し、これより表面の二
乗平均粗さを求め、更に、初期状態からの変化量を求め
て上記関係に当てはめることにより、使用を開始した初
期の段階から構造部材の疲労損傷度を得ることができる
ものとし、余寿命の予測を可能とする。Therefore, the relationship between the root-mean-square roughness of the surface of the test piece and the degree of fatigue damage is determined in advance, the shape of the surface of the structural member in use is measured, and the root-mean-square roughness of the surface is determined from this. By calculating the amount of change from the initial state and applying the relationship to the above relationship, the degree of fatigue damage of the structural member can be obtained from the initial stage of use, and the remaining life can be predicted.
【００１１】上記発明（２）は、種々実験を重ねた結
果、使用中の構造部材の表面の中心線平均粗さと疲労損
傷度との間には、相関関係があることを見出したことに
よるものであり、上記発明（１）と同様の手順で本発明
の測定方法を実施することにより、構造部材の表面の中
心線平均粗さと疲労損傷度の関係から、上記発明（１）
と同様に使用を開始した初期の段階からの構造部材の疲
労損傷度を得ることができるものとし、余寿命の予測を
可能としている。The above invention (2) is based on the finding that as a result of repeated experiments, there is a correlation between the center line average roughness of the surface of the structural member in use and the degree of fatigue damage. By performing the measuring method of the present invention in the same procedure as in the above invention (1), the relationship between the center line average roughness of the surface of the structural member and the degree of fatigue damage can be reduced.
In the same manner as described above, it is possible to obtain the degree of fatigue damage of the structural member from the initial stage of use, and it is possible to predict the remaining life.
【００１２】上記発明（３）は、種々実験を重ねた結
果、使用中の構造部材の表面の十点平均粗さと疲労損傷
度との間には、相関関係があることを見出したことによ
るものであり、上記発明（１）と同様の手順で本発明の
測定方法を実施することにより、構造部材の表面の十点
平均粗さと疲労損傷度の関係から、上記発明（１）と同
様に使用を開始した初期の段階からの構造部材の疲労損
傷度を得ることができるものとし、余寿命の予測を可能
としている。The above invention (3) is based on the finding that as a result of repeated experiments, there is a correlation between the ten-point average roughness of the surface of a structural member in use and the degree of fatigue damage. By performing the measurement method of the present invention in the same procedure as in the above invention (1), it is used in the same manner as in the above invention (1) because of the relationship between the ten-point average roughness of the surface of the structural member and the degree of fatigue damage. It is possible to obtain the degree of fatigue damage of the structural member from the initial stage when the process is started, and it is possible to predict the remaining life.
【００１３】[0013]
【実施例】本発明の第１実施例に係る構造部材の疲労損
傷度測定方法の手順について、以下に説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The procedure of a method for measuring the degree of fatigue damage of a structural member according to a first embodiment of the present invention will be described below.
【００１４】まず、繰返疲労負荷をうける構造部材につ
いて、計測対象部位の表面をダイヤモンド砥石１μｍに
よるバブ研磨により鏡面に仕上げた後、計測対象部位の
表面形状を最大負荷荷重方向に直線状に計測する。な
お、この際、計測には触針式等の接触式もしくはレーザ
ーによる計測等の非接触式の計測法を使用する。First, for a structural member subjected to a repeated fatigue load, the surface of the measurement target portion is mirror-finished by bub polishing with a diamond grindstone of 1 μm, and then the surface shape of the measurement target portion is measured linearly in the maximum load direction. I do. At this time, a non-contact measurement method such as a contact type such as a stylus type or a measurement using a laser is used for the measurement.
【００１５】次に、この計測により得られた構造部材の
計測対象部位の表面形状について、二乗平均粗さＲrms
を算出する。最後に、上記予め実験室で作成した試験片
についての二乗平均粗さＲrms と疲労損傷度との関係線
図に、上記算出結果を当てはめて疲労損傷度を求め、余
寿命を予測する。Next, regarding the surface shape of the measurement target portion of the structural member obtained by this measurement, the root-mean-square roughness Rrms
Is calculated. Finally, the degree of fatigue damage is determined by applying the above calculation result to the relationship diagram between the root mean square roughness Rrms and the degree of fatigue damage of the test piece prepared in advance in the laboratory, and the remaining life is predicted.
【００１６】本実施例については、種々実験を重ねた結
果、繰返疲労負荷を受ける使用中の構造部材の表面の二
乗平均粗さＲrms と疲労損傷度の間には、相関関係があ
ることを見出したことによるものである。なお、上記二
乗平均粗さＲrms は、次式により示されるものである。As a result of repeated experiments on the present embodiment, it was found that there is a correlation between the root mean square roughness Rrms of the surface of the structural member in use subjected to repeated fatigue loading and the degree of fatigue damage. This is due to the finding. The root mean square roughness Rrms is expressed by the following equation.
【００１７】[0017]
【数１】 (Equation 1)
【００１８】上記実験により得られた結果の一部を図１
及び図２により説明する。図１は、材料としてオーテナ
イト系ステンレス鋼であるＳＵＳＦ３１６Ｈを用いた丸
棒単軸試験片に繰返疲労負荷を与え、このときの試験片
の軸方向の表面形状の変化の計測結果（歪範囲Δε＝１
％時）を示したものである。FIG. 1 shows part of the results obtained by the above experiment.
And FIG. FIG. 1 shows a measurement result of a change in the axial surface shape of a test piece (a strain range Δε) in which a cyclic bar uniaxial test piece using SUSSF316H, which is an austenitic stainless steel as a material, was subjected to a repeated fatigue load. = 1
%).
【００１９】上記計測結果より二乗平均粗さＲrms を求
め、この増大分と疲労損傷度の関係を図示したものが図
２であり、図２より試験片の表面の二乗平均粗さと疲労
損傷度の間には、相関関係があることが判った。The root mean square roughness Rrms was determined from the above measurement results, and the relationship between the increase and the degree of fatigue damage is shown in FIG. 2. FIG. 2 shows the relationship between the root mean square roughness of the surface of the test piece and the degree of fatigue damage. It turns out that there is a correlation between them.
【００２０】上記表面形状の変化は、図１から判るよう
に疲労損傷の初期段階から表われるものであるため、本
実施例の方法は、構造部材の疲労損傷の初期段階におけ
る疲労損傷度の判定及び余寿命の予測に極めて有効なも
のである。Since the change in the surface shape is apparent from the initial stage of fatigue damage as can be seen from FIG. 1, the method of this embodiment determines the degree of fatigue damage in the initial stage of fatigue damage of a structural member. And it is extremely effective in predicting the remaining life.
【００２１】次に、本発明の第２実施例に係る測定方法
について説明する。本実施例の方法においては、第１実
施例における二乗平均粗さＲrms に代えて中心線平均粗
さＲａを用いており、測定方法実施の手順は第１実施例
と同様である。Next, a measuring method according to a second embodiment of the present invention will be described. In the method of the present embodiment, the center line average roughness Ra is used in place of the root mean square roughness Rrms in the first embodiment, and the procedure for implementing the measuring method is the same as in the first embodiment.
【００２２】本実施例についても、第１実施例と同様、
図１に示された測定結果より中心線平均粗さＲａを求
め、図３に示すようにこの増大分と疲労損傷度の間に相
関関係があることを見出したことによる。なお、上記中
心線平均粗さＲａは、次式により示される。In this embodiment, as in the first embodiment,
The center line average roughness Ra was determined from the measurement results shown in FIG. 1, and it was found that there was a correlation between the increase and the degree of fatigue damage as shown in FIG. The center line average roughness Ra is represented by the following equation.
【００２３】Ｒａ＝Ａ／Ｌ こゝで、Ａは図１に示すように振幅を繰返す表面粗さの
中心線に対する面積の絶対値の和であり、Ｌは振幅が計
測される軸方向の長さである。Ra = A / L where A is the sum of the absolute values of the area with respect to the center line of the surface roughness which repeats the amplitude as shown in FIG. 1, and L is the length in the axial direction where the amplitude is measured. That's it.
【００２４】次に、本発明の第３実施例に係る測定方法
について説明する。本実施例の方法においては、第１実
施例における二乗平均粗さＲrms に代えて十点平均粗さ
Ｒｚを用いており、測定方法実施の手順は第１実施例と
同様である。Next, a measuring method according to a third embodiment of the present invention will be described. In the method of the present embodiment, the ten-point average roughness Rz is used instead of the root mean square roughness Rrms in the first embodiment, and the procedure of the measurement method is the same as that of the first embodiment.
【００２５】本実施例についても、第１実施例と同様、
図１に示された測定結果より十点平均粗さＲｚを求め、
図４に示すようにこの増大分と疲労損傷度の間に相関関
係があることを見出したことによる。In this embodiment, as in the first embodiment,
A ten-point average roughness Rz was determined from the measurement results shown in FIG.
As shown in FIG. 4, it has been found that there is a correlation between the increase and the degree of fatigue damage.
【００２６】なお、十点平均粗さＲｚは、図１に示すよ
うに振幅を繰返す表面粗さの最も高い山から順に５番目
の山までの山頂の標高の平均値と、最も低い谷から順に
５番目の谷までの谷底の標高の平均値との差より求める
ものである。The ten-point average roughness Rz is, as shown in FIG. 1, the average value of the peak heights of the peaks from the highest peak of the surface roughness repeating the amplitude to the fifth peak, and the lowest valley. It is determined from the difference from the average value of the valley bottom up to the fifth valley.
【００２７】上記第１，第２，第３実施例の測定方法に
はそれぞれ特徴があり、以下にそれぞれの特徴について
比較説明する。第１実施例の場合は、計算が容易であ
り、全データの平均的特徴をつかむことができる。第２
実施例の場合は、計算は容易であるが、現状では他の２
つの方法に比べて精度が劣る。The measuring methods of the first, second, and third embodiments have respective features, and the respective features will be compared and described below. In the case of the first embodiment, calculation is easy, and an average feature of all data can be grasped. Second
In the case of the embodiment, the calculation is easy, but at present the other two
Accuracy is inferior to the two methods.
【００２８】第３実施例の場合は、１０点だけのデータ
にもとづくため、その点が損傷状況を代表するものでな
い場合には精度が低下する。なお、雑音や異物による凹
凸が表面粗さと計測される場合があるため、チェックを
要する。In the case of the third embodiment, since the data is based on only 10 points, the accuracy is reduced if the point is not representative of the damage situation. A check is required because irregularities due to noise or foreign matter may be measured as surface roughness.
【００２９】[0029]
【発明の効果】本発明の疲労損傷度測定方法において
は、予め、試験片に繰返疲労負荷を与えて表面の二乗平
均粗さ、中心線平均粗さ、又は十点平均粗さと疲労損傷
度の関係を求めておき、使用中の構造部材について表面
形状を計測し、その計測結果から表面の二乗平均粗さ、
中心線平均粗さ、又は十点平均粗さの変化を求め、これ
を上記予め試験片により求めた関係に当てはめて疲労損
傷度を求めるものとすることによって、表面形状計測と
いう簡便な方法で、使用中の構造部材の、特に初期段階
における疲労損傷および余寿命の定量的な把握を可能と
する。According to the method for measuring the degree of fatigue damage according to the present invention, a test piece is subjected to a repeated fatigue load in advance, and the root-mean-square roughness, center-line average roughness, or ten-point average roughness and the fatigue damage degree are determined. Is determined, the surface shape of the structural member in use is measured, and the root-mean-square roughness of the surface,
By calculating the change in the center line average roughness, or the ten-point average roughness, and applying the relationship to the relationship determined in advance by the test specimen to determine the degree of fatigue damage, by a simple method of surface shape measurement, It is possible to quantitatively grasp the fatigue damage and the remaining life of the structural member in use, particularly in the initial stage.
【図１】本発明の一実施例に係るそれぞれの疲労損傷度
における表面形状計測結果の説明図である。FIG. 1 is an explanatory diagram of a surface shape measurement result at each degree of fatigue damage according to one embodiment of the present invention.
【図２】上記一実施例に係る二乗平均粗さと疲労損傷度
の関係図である。FIG. 2 is a diagram showing a relationship between a root-mean-square roughness and a degree of fatigue damage according to the embodiment.
【図３】本発明の第２実施例に係る中心線平均粗さと疲
労損傷度の関係図である。FIG. 3 is a diagram showing a relationship between a center line average roughness and a degree of fatigue damage according to a second embodiment of the present invention.
【図４】本発明の第３実施例に係る十点平均粗さと疲労
損傷度の関係図である。FIG. 4 is a diagram illustrating a relationship between a ten-point average roughness and a degree of fatigue damage according to a third embodiment of the present invention.
フロントページの続き (56)参考文献 特開 昭54−69494（ＪＰ，Ａ) 特開 平５−87717（ＪＰ，Ａ) 特開 平５−72087（ＪＰ，Ａ) 材料力学部門講演会講演論文集，社団 法人 日本機械学会，1995年 ８月18 日，Ｖｏｌ．Ｂ Ｎｏ．95−２，ｐ. 412−413 (58)調査した分野(Int.Cl.7，ＤＢ名) G01N 3/00 - 3/62 G01N 17/00 - 17/04 ＪＩＣＳＴファイル（ＪＯＩＳ)Continuation of the front page (56) References JP-A-54-69494 (JP, A) JP-A-5-87717 (JP, A) JP-A-5-72087 (JP, A) Proceedings of the lecture meeting of the Mechanics of Materials , The Japan Society of Mechanical Engineers, August 18, 1995, Vol. B No. 95-2, p.412-413 (58) Fields surveyed (Int. Cl. 7 , DB name) G01N 3/00-3/62 G01N 17/00-17/04 JICST file (JOIS)
Claims (3)
験片について表面の二乗平均粗さと疲労損傷度の関係を
求めておき、使用中の構造部材について計測対象部位表
面を鏡面に仕上げた後、最大負荷荷重方向に直線状に表
面の形状を計測し、この計測結果から二乗平均粗さを計
算し、更に、この二乗平均粗さについて初期状態からの
変化量を求めた後、上記予め求めた二乗平均粗さと疲労
損傷度の関係から上記構造部材の疲労損傷度を求めるこ
とを特徴とする疲労損傷度測定方法。1. The relationship between the root mean square roughness of a surface of a test piece of a structural member subjected to repeated fatigue load and the degree of fatigue damage is determined in advance, and the surface of a measurement target portion of the structural member in use is finished to a mirror surface. The surface shape is measured linearly in the direction of the maximum load, the root-mean-square roughness is calculated from the measurement results, and the root-mean-square roughness is determined in advance from the initial state. A method for measuring the degree of fatigue damage of the structural member from the relationship between the root mean square roughness and the degree of fatigue damage.
おいて、二乗平均粗さに代えて中心線平均粗さを用いる
ことを特徴とする疲労損傷度測定方法。2. The method according to claim 1, wherein a center line average roughness is used instead of a root mean square roughness.
おいて、二乗平均粗さに代えて十点平均粗さを用いるこ
とを特徴とする疲労損傷度測定方法。3. The fatigue damage measuring method according to claim 1, wherein ten-point average roughness is used instead of root mean square roughness.
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| JP5370022B2 (en) * | 2009-09-07 | 2013-12-18 | 株式会社Ｉｈｉ | Method and apparatus for estimating low cycle fatigue characteristics |
| JP5678776B2 (en) * | 2011-03-31 | 2015-03-04 | 株式会社Ihi | Fatigue strength estimation method and apparatus based on machining finish |
| CN111678821A (en) * | 2020-06-23 | 2020-09-18 | 山东大学 | Low-cycle fatigue life prediction method based on high-temperature alloy processing surface integrity |
| CN114812484B (en) * | 2022-03-30 | 2024-02-13 | 中国有研科技集团有限公司 | Efficient checking method for effective life of wedge welding chopper |
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