Loading Methods

Flexible and Efficient: One sensor system for dynamic, thermal and vacuum loading.


Dynamic Loading

For the dynam­ic load­ing the piezoshak­er exci­ta­tion sys­tems are designed by isi-sys. It con­sists of a Piezoshak­er, ampli­fi­er and func­tion gen­er­a­tor. For a detailed descrip­tion please refer to the report “Prod­ucts / Piezoshak­er Systems ”

The video on the right shows the lamb waves, gen­er­at­ed by the piezoshak­er, that is attached at the bot­tom of the spec­i­men. The waves trav­el across the object sur­face and excite the five local sub­sur­face defects on the top. The local defects vibrate dif­fer­ent­ly, depend­ing on their local mechan­i­cal prop­er­ties (stiff­ness). Only very lit­tle pow­er of the piezoshak­er is required, when the exci­ta­tion fre­quen­cy is close to the local defect res­o­nance fre­quen­cy. This prin­ci­ple is used in non-destruc­tive test­ing for exam­ple, espe­cial­ly to locate delam­i­na­tions in sand­wich structures.




The Piezoshak­er can be attached by vac­u­um to the object sur­face. The HVDA‑0–180 ampli­fi­er is espe­cial­ly design for isi-sys Piezoshak­ers and mobile appli­ca­tion, where high pow­er at low weight and com­pact size is a big advan­tage for mobil­i­ty and flex­i­ble han­dling. High fre­quen­cies up to 100kHz and more as well as large forces and accel­er­a­tion have been gen­er­at­ed in com­bi­na­tion with the dif­fer­ent isi-sys Piezoshak­er modules.









Thermal LoadingThermal loading

isi-sys offers timed ther­mal load­ing mod­ules to to heat-up the objects of measurement.

A auto­mat­ed pre­cise con­trol of heat load­ing and a cor­re­spond­ing timed shearo­graph­ic mea­sure­ment is required to achieve a repro­ducible test pro­ce­dure for non destruc­tive test­ing exper­i­ments and auto­mat­ed systems.

Any con­ven­tion­al halo­gen flood lights with 220V can be con­nect­ed. isi-sys rec­om­mends some flood lights used for pro­fes­sion­al pho­tog­ra­phy. Thus they can be mount­ed on stan­dard light stand of e. g. Man­frot­to etc. and eas­i­ly direct­ed to the area of inter­est inde­pen­dent of the sen­sor head. Also this lights offer some choic­es of reflec­tor combinations.

The start and dura­tion of the heat load­ing and the mea­sure­ments can be set per com­put­er con­trolled timer, which per­mits repro­ducible sequences of the test process.







Vakuum Loading

The vac­u­um is anoth­er load­ing method for non destruc­tive test­ing. The mod­u­lar sys­tem con­cept allows to com­bine the SE2 sen­sor with dif­fer­ent vac­u­um load­ing devices, which reduces sys­tem expense and keeps the equip­ment smart and mobile com­pared to oth­er solutions .

The vac­u­um meth­ods can be cat­e­go­rized depend­ing on the load­ing prin­ci­ple into vac­u­um chambers/vacuum cab­ins and vac­u­um hood/vacuum windows.


Vacuum hood and Vacuum window

Vakuum hoodThe vac­u­um hood is a mod­u­lar exten­sion acces­sories for the SE2 sen­sor. The sen­sor will be mount­ed inside of the hood and ther­fore the mea­sure­ment area is cov­ered from sun light influences.

The sys­tem has small dimen­sions and is for this rea­son very mobile and flex­i­ble, addi­tion­al­ly the low required vac­u­um pump pow­er is an advantage.





Vakuum window

If you use the vac­u­um win­dow, the sen­sor is out­side the vac­u­um vol­ume. The sys­tem is mon­i­tor­ing the object through the win­dow. The bend­ing forces are only across the field of view.

Due to the small vol­ume of the vac­u­um win­dow hood it can be used in com­bi­na­tion with the small isi-vac­u­um unit (also used for isi-piezoshak­ers with vac­u­um cup adapter). The unit includes two sep­a­rate vac­u­um pumps, where the sec­ond can be used for the vac­u­um suc­tion cup tripod.



Vacuum chamber and Vacuum cabin

Gen­er­al­ly vac­u­um cham­bers or cab­ins have the advan­tage against vac­u­um hoods and win­dows, that the forces appear uni­form from all sides on the object. This avoids super­posed fringes by glob­al defor­ma­tion such as by hood, where a bend­ing force on the object sur­face is super­posed, as usu­al­ly the pres­sure forces are applied only in one direc­tion on one side of the sur­face, where the hood is applied.

In both sys­tems the sen­sor is inside the vac­u­um vol­ume, which caus­es pres­sure load­ing also on the sen­sor. The cam­ber and the cab­in are big­ger than the object and there­fore depend­ing on object size the mobil­i­ty is restricted.

isi-sys offers the new­ly designed test­ing vac­u­um cab­in based on alu­mini­um-foam sand­wich ele­ments, which is rec­om­mend­ed e. g. for fre­quent­ly man­u­al spot tests or lab­o­ra­to­ry use.  Sam­ples with a size up to 450 x 750 mm can be mea­sured in this cabin.

Fur­ther­more isi-sys GmbH coop­er­ates with dif­fer­ent man­u­fac­tur­er for large vac­u­um chambers.






SE-Sensors Types

No safe­ty require­ments: Laser class 1 with pow­er from 0,1W up to 12W per module

High res­o­lu­tion and sen­si­tiv­i­ty: 5 MPix­el sen­sor, 10nm light phase reconstruction

High qual­i­ty and vari­ety of lens­es: Designed for pro­fes­sion­al Nikon-F-mount lenses


SE1 Sensor

SE1 shearography


The SE1 sen­sor mod­u­lar system

for auto­mat­ed appli­ca­tions such

as tire testing.







SE2 Sensor



SE2 Sen­sor with 1W light pow­er by

10 adjustable laser diodes for flexible

lab­o­ra­to­ry use. The SE2 is the most

flex­i­ble and recent­ly new upgraded

design in the SE-sen­sor family.





SE2 neu array



SE2 Sen­sor with 12 W laser diode module

for out­door and large field of view








SE3 Sensor



SE3 Sen­sor




Software: isi-Studio

isi-Stu­dio is a spe­cial­ized soft­ware tool for auto­mat­ic and man­u­al con­trolled oper­at­ing and record­ing of (speck­le) interferometry.

The work-flow ker­nel of isi-Stu­dio records the user oper­a­tions. Its recall and re-do options of any oper­a­tion sequences offers facil­i­ties to con­trol indi­vid­ual research set ups as well as auto­mat­ic solu­tions for indus­try prob­lems. Remote con­trolled fea­tures such as shear­ing are fea­tures in con­junc­tion with the sen­sor series.

Typ­i­cal appli­ca­tions of isi-stu­dio are non destruc­tive test­ing (NDT), vibra­tion analy­sis, strain and defor­ma­tion measurements.

Solution Features

Auto­mat­ic project and work-flow man­age­ment: each oper­a­tion step of your mea­sure­ment or image oper­a­tion is recorded.


Expo­sure of speck­le inter­fer­o­grams in dif­fer­ent acqui­si­tion tech­niques, such as real time phase recon­struc­tion and time aver­age tech­nique with renewed ref­er­ence frame.




isi-Stu­dio offers var­i­ous stan­dard fil­ter-types and spe­cial fil­ters adapt­ed to dis­con­ti­nu­ities of phase maps.





isi-Stu­dio con­tains a robust demod­u­la­tion or unwrap­ping algo­rithm that removes the phase steps and con­verts the fil­tered phase map into a con­tin­u­ous plot.

If your phase map is fil­tered and demod­u­lat­ed, there is the choice to use auto­mat­ic eval­u­a­tion of the para­me­ters, such as the wave length of the light source used, saved in the image prop­er­ty sheets dur­ing the measurements.


isi-studio4For pre­sen­ta­tion or analy­sis of your results, isi-Stu­dio offers tools such as 2D or 3D plots. If you want to include your results into oth­er doc­u­ments, you have the choice of com­mon input and out­put image for­mats (bmp, tiff, jpg, etc.) as well as the com­pat­i­bil­i­ty for numer­i­cal exchanges to Math-Lab, Excel and oth­er soft­ware. Alter­na­tive the report gen­er­a­tor can be used to cre­ate a report document.




An prac­ti­cal exam­ple to eplain the the func­tion­al­i­ty of isi-Stu­dio:x


Phasenrekonstruktion Gefilterte-Phasenaenderung Demodulierte-Phasenverteilung

Recontruction:relative phase change     Fil­tered phase change                        Demod­u­lat­ed phase distribution

Falschfarbendarstellung-bzw-Quantitaqtiv Integration-Verformungsamplitude Falschfarbendarstellung-Quantitativ

False-colour image                                Inte­gra­tion: defor­ma­tion ampli­tude      Quan­ti­ta­tive false-colour image