Although labor relations are for the most part peaceful compared with the turbulent decades just after World War II, union-related violence remains ''a blight on industrial relations'' that should be curbed by tougher government action, according to a study just released by the University of Pennsylvania's Wharton School.
''There can be no remaining doubt that labor violence is a real and continuing problem. Its presence is a blight on industrial relations that arises with distressing frequency during organization drives and strikes,'' said the study by Armand Thiebolt Jr. and Thomas Haggard, under the direction of Herbert Northrup, a professor of industry.
Laws covering violence in labor disputes ''generally reflect an attitude of indifference to the effects'' of disorders such as those that have occurred, most recently, in copper industry and telephone strikes.
The study recommends a tougher response in courts, Congress, state legislatures, and the National Labor Relations Board.
The study found that violence was most common during mass picketing, where emotions run high and group cover enables individuals to act aggressively because they have less fear of arrest or reprisals. Generally, according to the study, violence now occurs most frequently:
* Among union groups with long records of militancy. Examples include the copper miners' early attacks on strike breakers employed by the Phelps Dodge Corporation in Arizona, frequent violence by members of the International Brotherhood of Teamsters against nonunion truckers in labor disputes, and violence by some members of the United Mine Workers in the coal fields.
* In angry confrontations with employers when usually smooth relationships run into bargaining snags. This happened recently during the telephone strike when costly vandalism of Bell System lines and equipment in New Jersey and elsewhere were linked to emotional flare-ups among strikers.
Copper-mine and refinery workers, represented in the nonferrous industry by the United Steelworkers and several smaller unions, have a background of militancy and independence. This year, the steel union and its allies negotiated peacefully with most major mine employers in the industry. But Phelps Dodge management offered its unionized workers contract terms that were less than the industry pattern. The workers struck. When the company announced plans to hire replacement workers to keep mines and refineries operating during the strike, picket-line disorders erupted quickly. Four hundred Arizona National Guard troops and 425 state and local police were called out to maintain peace. Most have now left the struck operations.
The telephone strike by the Communications Workers of America and two other unions involved fears of lost jobs as the Bell System reorganizes operations and becomes more automated. As telephone service continued, violence - in the form of vandalism to Bell System property - spread quickly.
The report found the Teamsters to be the most violent union, with 384 incidents recorded between 1975 and 1981, when authors of the study checked 3, 000 cases of union-related violence. The United Mine Workers came second with 204 incidents; the United Steelworkers, with 130; the United Automobile Workers, 128; and the American Federation of State, County, and Municipal Employees was fifth with 116. Increasing violence in labor actions by hospital and health care unionists was indicated by 57 incidents.