EP0413696A1 - Appareil pour essais au choc - Google Patents

Appareil pour essais au choc

Info

Publication number
EP0413696A1
EP0413696A1 EP19890903195 EP89903195A EP0413696A1 EP 0413696 A1 EP0413696 A1 EP 0413696A1 EP 19890903195 EP19890903195 EP 19890903195 EP 89903195 A EP89903195 A EP 89903195A EP 0413696 A1 EP0413696 A1 EP 0413696A1
Authority
EP
European Patent Office
Prior art keywords
impact
weight
ground
arm
testing apparatus
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.)
Withdrawn
Application number
EP19890903195
Other languages
German (de)
English (en)
Inventor
Michael Ian Cobbe
Leonard Threadgold
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GEOTECHNICS Ltd
Original Assignee
GEOTECHNICS Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by GEOTECHNICS Ltd filed Critical GEOTECHNICS Ltd
Publication of EP0413696A1 publication Critical patent/EP0413696A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/30—Investigating strength properties of solid materials by application of mechanical stress by applying a single impulsive force, e.g. by falling weight
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D1/00—Investigation of foundation soil in situ
    • E02D1/02—Investigation of foundation soil in situ before construction work
    • E02D1/022—Investigation of foundation soil in situ before construction work by investigating mechanical properties of the soil
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M7/00—Vibration-testing of structures; Shock-testing of structures
    • G01M7/08—Shock-testing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/003—Generation of the force
    • G01N2203/0032—Generation of the force using mechanical means
    • G01N2203/0039—Hammer or pendulum

Definitions

  • This invention relates to an impact testing apparatus for use in carrying out impact tests on ground, soil or similar materials.
  • One known form of impact tester comprises a cylindrical weight which is free to slide within an upright tube placed on the ground which is to be tested. In use, the weight is raised within the tube and then dropped from a fixed height so as to impact onto the ground. The weight is provided with an accelerometer connected to a readout so as to give a measure of the deceleration of the weight at the instant of impact. Whilst this form of impact tester is useful it has certain recognised drawbacks, including the following. Firstly, the weight is of relatively small diameter so that the reliability of the measurement given by the read-out will depend upon the average size of the stones etc. which make up the ground surface.
  • the test tends to cause bearing failure in the material being tested rather than testing within the range of stress up to failure in which the material would be required to function in practice.
  • the tester requires the weight to be pulled up the vertical tube manually prior to each drop: this places strain on the user's back and the size of the weight and drop height which can be used is limited.
  • it is necessary to ensure that the tube is vertical and the surface to be tested horizontal.
  • an impact testing apparatus comprising a weight mounted to a pivoted arm and arranged so that the weight will swing under gravity about the pivot and impact with the ground perpendicular to the latter.
  • the weight is exposed rather than being contained within an upright tube, it may be of larger cross-section. Moreover, the weight may be made removable and replaceable by others of different size and weight to suit the application. There is no risk of the weight being retarded by rubbing aganst any guide channel or tube. Any convenient arrangement may be provided for raising the weight prior to each drop, such as a length of cable which the user can pull on. This places less strain on the user than if he were required to pull a weight vertically upwards.
  • the weight may be raised to any required angle of the pivoted arm and preferably a transducer is provided to give a read-out of the angular position of the arm.
  • the impact testing apparatus is preferably provided with wheels or the like so that it may be pushed or pulled by hand between positions at which impact tests are to be made.
  • the apparatus may be provided with a pair of wheels or a roller at one end, arranged to come into contact with the ground and support the apparatus when this is lifted at the other end, in the manner of a wheelbarrow.
  • the weight may be provided with an accelerometer coupled to a read-out for giving a measure of the deceleration of the weight at impact.
  • the apparatus may alternatively or instead be provided with arrangements for carrying out one or more other impact tests, such as measuring the depth to which the weight penetrates the ground upon impact, or the distance through which it rebounds.
  • FIGURE 1 is a plan view of an impact testing apparatus in accordance with the invention.
  • FIGURE 2 is a side view of the apparatus; and FIGURE 3 is a section through a loading plate set for use with the apparatus.
  • an impact testing apparatus comprising a frame 10 mounting an arm 12 which is pivoted at one end to the frame by means of a shaft 14 and carries a cylindrical boss 15 at its other end, to which weights 16, 17 are attached.
  • the weights 16, 17 are circular but are removable from the top and bottom of the boss 15 and can be replaced by weights of different shapes and sizes to suit the particular application of use.
  • the weights 16, 17 may each be in the range of 5 to 8 kg with diameters in the range 100-300 mm although weights in excess of 10kg may be used.
  • the arm 12 might typically have a length of 750 mm.
  • the frame 10 comprises two inclined side members 10a, 10b, a cross-member 10c at the wider end and a foot plate 11 across the narrower end.
  • Wheels 18 are mounted to projections 20 of the side members 10a, 10b at the wider or forward end of the frame.
  • the frame 10 rests flat on the ground G via two feet 24 on the side members adjacent the forward end of the frame and a foot 25 at the narrower or rearward end.
  • the arm 12 is fixed to the shaft 14 which is journalled at its opposite ends in blocks 26 which are slidably mounted to vertical guideways 27.
  • the shaft 14 also passes through an adjustment block 28 through which a vertical adjustment shaft 29 is threaded.
  • Adjustment shaft 29 can be turned by means of a wheel 30 at its upper end, in order to adjust the height of the pivot shaft 14 above the footplate and so bring the arm 12 into a line parallel with the ground when the weight 16 is resting on the ground.
  • a shaft encoder 31 is coupled to the pivot shaft 14 and provides a signal to an electronic unit 32 to display the angular position of the arm 12 relative to the horizontal.
  • a pull- cable 33 is connected to any eye 34 on a bolt which fastens the weight 17 to the top of the boss 15. The user may pull the arm up using the pull cable 33 whilst standing on the footplate 11.
  • the lower end of the boss 15 is provided with an accelerometer 13 which relays a signal over a communication cable extending along the arm 12 to the unit 32 which determines and displays a measure of the peak or maximum deceleration of the weight at impact, and also the time delay between the onset of deceleration and the peak.
  • an accelerometer 13 which relays a signal over a communication cable extending along the arm 12 to the unit 32 which determines and displays a measure of the peak or maximum deceleration of the weight at impact, and also the time delay between the onset of deceleration and the peak.
  • the apparatus can be moved manually by lifting at the rearward end of the frame so that the wheels 18 come into contact with the ground and the frame itself is lifted out of contact with the ground.
  • the arm 12 now rests on an underslung cross- piece 19 of the frame.
  • the apparatus can then be pushed or pulled in the manner of a wheelbarrow.
  • three or four running wheels may be provided for the apparatus to run on, these wheels being raised off the ground to place the frame flat on the ground when the apparatus is to be used.
  • the apparatus may be used on ground which is level or sloping, but in any event the weight will impact against the ground in a direction (at the instant of impact) which is perpendicular to the ground surface.
  • the apparatus which has been described is a portable, low-cost test apparatus which allows one-man operation for applying repeated impacts from variable masses.
  • the total weight (weights 16 plus weight 17) may exceed 20 kg and the weights may be of selected diameters and dropped through selected heights e.g. up to 750 mm.
  • the falling mass strikes the surface of the material under test orthogonally and a measure is made of an elastic response over a depth of similar order to the depth of a compacted layer of soil or stabilised or granular material as used in civil engineering construction.
  • the height of the pivot shaft 14 is adjusted to ensure that the arm 12 is parallel to the plane of the frame 10, the display giving a read-out of zero.
  • the electronic unit 32 giving read-outs of the peak deceleration (orthogonal dynamic impact number - ODIN) and of the time delay TP to reach the peak from the onset of the detected deceleration.
  • the deceleration can be recorded over different drop heights H and the relationship between ODIN and H can be used to indicate the range of conditions under which the response of the material under test will be elastic, and also the points at which the response becomes plastic (with largely non-recoverable deformation of the impacted material) can be determined.
  • This provides a range of operating conditions to enable the apparatus to be adjusted (i.e. the magnitude and diameters of the weights and the drop height to be selected) in order to suit varying materials and site conditions.
  • the measured values ODIN and TP can be used to calculate an apparent modulus, on impact (AMI) using a simple formula which permits of rapid hand calculation.
  • AMI apparent modulus, on impact
  • rapid testing within a particular situation can be carried out using measurement of peak deceleration (ODIN) alone.
  • Anomalous conditions can be investigated non-destructively by measuring the impact response using different weight diameters whilst continuing to ensure that the loading is within the elastic response range of the material under test.
  • a loading plate set may be laid on the ground and itself impacted by the weight 16.
  • the set ( Figure 3) includes top and bottom plates 40, 41 with a resilient layer 42 (e.g a polymeric layer or an assembly of springs) in between.
  • the effect under impact onto the top plate 40 is that the underlying ground material is subjected to a load pulse of extended duration simulating that applied by the wheel of a vehicle moving over the surface.
  • Transient and permanent deflections of the lower plate 40 are measured by an array of contact-less displacement transducers 43 mounted on a ring which is supported on an arm 46 cantilevered from a counterbalance block 48 at a remote location and adjustable for height and inclination.
  • the maximum applied stress may be determined from the deceleration of the dropped weight or from the mean of the displacements of the spring system measured by the further displacement transducers which record the relative displacement between the top and bottom plates.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Immunology (AREA)
  • General Health & Medical Sciences (AREA)
  • Biochemistry (AREA)
  • Pathology (AREA)
  • Soil Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)

Abstract

Appareil utilisé pour effectuer des essais au choc sur le sol comprenant un poids (15, 16, 17) monté sur un bras pivotant (12) et disposé de manière à osciller, par l'effet de la gravité, autour d'une pointe de pivot (14) du bras et à frapper le sol dans une direction sensiblement perpendiculaire à celui-ci. Cet appareil peut être manipulé par une seule personne; celle-ci peut soulever le bras (12) à l'aide d'un câble jusqu'à une hauteur prédéterminée indiquée par un capteur rotatif placé sur la pointe de pivot (14). Le poids est pourvu d'un accéléromètre et le freinage maximum à l'impact est mesuré, de même que le temps nécessaire pour atteindre ce freinage maximum, à compter du début du freinage; ces mesures permettent de calculer l'amplitude apparente de l'impact pour le sol faisant l'objet des essais.
EP19890903195 1988-02-05 1989-02-03 Appareil pour essais au choc Withdrawn EP0413696A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB888802626A GB8802626D0 (en) 1988-02-05 1988-02-05 Impact testing apparatus
GB8802626 1988-02-05

Publications (1)

Publication Number Publication Date
EP0413696A1 true EP0413696A1 (fr) 1991-02-27

Family

ID=10631149

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890903195 Withdrawn EP0413696A1 (fr) 1988-02-05 1989-02-03 Appareil pour essais au choc

Country Status (4)

Country Link
EP (1) EP0413696A1 (fr)
AU (1) AU3975889A (fr)
GB (1) GB8802626D0 (fr)
WO (1) WO1989007176A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1975337A1 (fr) 2007-03-20 2008-10-01 Hussor (Société par Actions Simplifiée) Dispositif de serrage de deux banches en bout

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5105650A (en) * 1990-03-08 1992-04-21 Gas Research Institute Monitoring compaction of backfill
ES2285393T3 (es) * 2004-01-16 2007-11-16 Mondo S.P.A. Procedimiento e instrumento para caracterizar una superficie de pisado, por ejemplo una superficie de cesped sintetico.
US8511139B2 (en) 2011-02-28 2013-08-20 Research In Motion Limited Systems and methods for impact testing
EP2492664A1 (fr) * 2011-02-28 2012-08-29 Research In Motion Limited Systèmes et procédés pour les tests d'impact
WO2016067148A1 (fr) * 2014-10-26 2016-05-06 Gåård Anders Caractérisation de plancher
CN110530741A (zh) * 2019-09-25 2019-12-03 辽宁工业大学 一种可同时批量测试的全自动落锤冲击试验机
CN112557167A (zh) * 2020-12-18 2021-03-26 山东科技大学 一种原位煤体冲击倾向性观测方法
CN115235738B (zh) * 2022-09-21 2022-12-13 廊坊开发区中油新星电信工程有限公司 精确定位埋地光缆故障位置的地面振动测试设备

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3946598A (en) * 1974-07-11 1976-03-30 Robin M. Towne And Associates, Inc. Method and apparatus for determining the dynamic parameters of soil in situ
GB1524445A (en) * 1975-03-17 1978-09-13 Univ Western Australia Impact soil testing device
FR2533030B1 (fr) * 1982-09-09 1986-04-25 Adhout Hertsel Balistometre pour la mesure des proprietes elastiques de la peau
FR2599150B1 (fr) * 1986-05-21 1988-09-16 Exper Rech Etu Batimen Centre Procede et dispositif de controle mecanique de revetements d'ouvrages d'art

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8907176A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1975337A1 (fr) 2007-03-20 2008-10-01 Hussor (Société par Actions Simplifiée) Dispositif de serrage de deux banches en bout

Also Published As

Publication number Publication date
WO1989007176A1 (fr) 1989-08-10
AU3975889A (en) 1989-08-25
GB8802626D0 (en) 1988-03-02

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